Loading...

Table of Content

    01 May 2017, Volume 50 Issue 9
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
    Identification and Gene Mapping of a Dwarf and Curled Flag Leaf Mutant dcfl1 in Rice (Oryza sativa L.)
    ZHANG XiaoBo, XIE Jia, ZHANG XiaoQiong, TIAN WeiJiang, HE PeiLong, LIU SiCen, HE GuangHua, ZHONG BingQiang, SANG XianChun
    Scientia Agricultura Sinica. 2017, 50(9):  1551-1558.  doi:10.3864/j.issn.0578-1752.2017.09.001
    Abstract ( 567 )   HTML ( 6 )   PDF (2203KB) ( 648 )   Save
    References | Related Articles | Metrics
    【Objective】Leaf blade is an important factor of plant type, which is directly related to leaf photosynthetic area and light energy utilization. Flag leaf is most prominently in the formation of rice production. Study of the genes which regulate flag leaf development in rice is of very significance in rice functional genomics research and molecular breeding. A novel flag leaf mutant has been identified and the results of study will provide a foundation for the research of leaf morphological formation and plant type breeding in Oryza sativa L.【Method】A dwarf and curled flag leaf mutant (dcfl1) was discovered from the progeny of indica restorer line Jinhui10 with seeds treated by ethyl methane sulfonate (EMS) and the traits of dwarf and curled flag leaf base inherited steadily after multi-generations’ self-fertility. The second leaf sheath was observed by scanning electron microscopy (SEM) at the three-leaf stage. The flag leaf base was used for paraffin section at the booting and heading stages. At the blooming stage, the characteristics of chloroplast pigment of the flag, second and third leaf blades were measured. At the maturity stage, agronomic traits such as plant height, panicle length, efficient panicle per plant, seed number per panicle, filled grain number per panicle, seed setting ratio, and 1000-seed weight were measured. The dcfl1 was crossed with indica sterile line Xinong 1A, and the F1 and F2 generations were used for genetic analysis. Additionally, gene mapping was performed based on the recessive individuals of the F2 generation of Xinong 1A/ dcfl1.【Result】The dcfl1 was dwarf in all phases of plant development. The cell length of the 2nd leaf sheath surface of the dcfl1 was significantly shorter than the wild type. The panicle length, the first and the second internode of the dcfl1 were all significantly shorter than those of the wild type. The dcfl1 displayed a severe curl at the base of flag leaf blade after the heading stage, while the upper of flag leaf blade was nearly normal in the flag leaf. Meanwhile, the other leaf blades appeared as normal as the wild type. No significant differences were detected in grain number per panicle, filled grain number per panicle, seed setting rate and 1000-seed weight between the dcfl1 and the wild type. However, the number of the tiller in the dcfl1 was more than the wild type and the efficient panicle per plant was increased significantly than the wild type. Having the dark green leaves, the contents of chlorophyll a and total chlorophyll in the dcfl1 increased significantly compared with those of the wild type for the flag leaves, the second and the third leaves. Genetic analysis indicated that the dwarf and curled flag leaf traits of dcfl1 were controlled by a recessive nuclear gene. Based on the F2 population derived from a cross between the dcfl1 and an indica sterile line, Xinong 1A, the gene was fine mapped on chromosome 3 between InDel marker Ind03-11 and Ind03-6 with the physical distance 78 kb, containing fifteen annotated genes.【Conclusion】The dcfl1 is a novel recessive dwarf and curled flag leaf mutant coming from EMS-inducement. The DCFL1 was mapped on chromosome 3 with 78 kb physical distance. These results will provide a foundation for map-based cloning of DCFL1 gene and understanding of the molecular mechanism of the rice flag leaf.
    Isolation of GmHAT5 from Glycine max and Analysis of Saline Tolerance for Transgenic Lotus japonicus
    KE DanXia, LI XiangYong, WANG Lei, CHENG Lin, LIU YongHui, LI XiaoYan, WANG HuiFang
    Scientia Agricultura Sinica. 2017, 50(9):  1559-1570.  doi:10.3864/j.issn.0578-1752.2017.09.002
    Abstract ( 289 )   HTML ( 2 )   PDF (3542KB) ( 750 )   Save
    References | Related Articles | Metrics
    【Objective】Based on RNA-Seq profiling of the homeodomain leucine zipper protein (HD-Zip) transcription factor family in soybean (Glycine max) during salt stress, screening and cloning of a salt-induced gene (GmHAT5) from soybean were conducted. GmHAT5 was transformed into Lotus japonicus, the legume model system, to further understand the mechanism of salt tolerance. 【Method】The ORF of GmHAT5, the protein molecular weight, isoelectric point, sequence structure and protein localization were analyzed by some bioinformatics programs. Meanwhile, the homologous protein alignments with 10 other species, and relative expression levels of GmHAT5 in different organs and under saline stress were also analyzed. The overexpression vector of GmHAT5 was constructed and transformed into Agrobacterium rhizogenes strain LBA1334 to obtain the “composite” Lotus japonicus plants and the salt resistant phenotype was analyzed under salt stress. The overexpression vector of GmHAT5 was also transformed into Agrobacterium tumefaciens strain EHA105 to obtain the stable transgenic Lotus japonicus plants and then the phenotype and related physiological indexes were analyzed under salt stress. 【Result】Bioinformatics software analysis showed that the GmHAT5 contained an ORF with 1 038 bp, encoded 345 amino acid. The theoretical molecular weight and isoelectric point of GmHAT5 protein were 39.17 kD and 4.63, respectively. GmHAT5, located in the nucleus as other HD-Zip family proteins, was a typical nuclear protein. Sequence analysis showed that GmHAT5, which belonged to the first class of plant HD-Zip protein, contained a homeobox domain and a leucine zipper domain. The homologous protein alignments showed that GmHAT5 had a high similarity with GsHAT5. The hairy root transformation result showed that, after being treated with 200 mmol·L-1 NaCl for 7 d, the “composite” plants grew well, while the empty vector control plants exhibited discoloration and stunted growth. Transgenic hairy roots in vitro culture was treated with a different concentration of NaCl for 14 d. Compared with the overexpressing transgenic hairy roots, the control group shriveled up and its growth was inhibited significantly. Stable transformation result showed that, after being treated with different concentration of NaCl for 14 d, the transgenic plants grew well compared to the two control groups. There were significantly changes in malondialdehyde content and relative membrane permeability caused by saline stress in transgenic plants compared to the two control groups (P<0.05). Moreover, transgenic plants had higher levels of chlorophyll content and root activity compared with the two control groups under saline stress conditions (P<0.05). Compared with the control plants, transgenic plants had lower levels of Na+ content in leaves and roots, while K+ and Ca2+ contents in leaves and roots increased significantly in transgenic plants.【Conclusion】 A HD-ZipⅠclass homeodomain leucine zipper protein gene (GmHAT5) was cloned from soybean, the expression level was significantly increased under salt stress. Over-expression of GmHAT5 gene could enhance resistance to saline in Lotus japonicus. Hairy root transformation method could be used as a quick effective means for screening of salt tolerance candidate gene. These imply that GmHAT5 may play an important role in salt stress regulation in soybean.
    Cloning and Expression Analysis of TAD1 (ScTAD1) in Sugarcane
    LI XuJuan, ZI QiuYan, LI ChunJia, LIU HongBo, LIN XiuQin, XU ChaoHua, LU Xin, MAO Jun, LIU XinLong
    Scientia Agricultura Sinica. 2017, 50(9):  1571-1581.  doi:10.3864/j.issn.0578-1752.2017.09.003
    Abstract ( 386 )   HTML ( 6 )   PDF (7615KB) ( 405 )   Save
    References | Related Articles | Metrics
    【Objective】The Tillering and Dwarf 1 (TAD1) gene plays an important role in regulating plant architecture, and response to the forming and developing of lateral buds. In this study, the gene named ScTAD1 was cloned from sugarcane, the structure and function of it were estimated, and the expression characteristics in different sugarcane tissues, axillary buds at different development at stages and seedlings treated by auxin and cytokinin were screened to provide a reference for function analysis of ScTAD1 and molecular assisted selection of sugarcane yield in the future. 【Method】 A series of technologies including in silico cloning, reverse transcription PCR (RT-PCR) and rapid-amplification of cDNA ends (RACE) were used to obtain the full-length cDNA of ScTAD1, the structure and function of this gene were analyzed and predicted using bioinformatics methods. Finally, by using the real-time fluorescent quantitative PCR (qPCR) technique, the expression pattern of this gene was detected in six different tissues (root, stem, leaf, tiller bud, leaf sheath and stem apex), stem apex and axillary buds with different size (tender axillary bud, medium axillary bud, largish axillary bud, mature dormant axillary bud) and six different time points of seedling tip with non-elongated internodes treated by IAA and 6-BA.【Result】The full length cDNA of ScTAD1 (GenBank accession number: KX611166) was obtained, which contains a 1 560 bp complete open reading frame (ORF) and encodes 519 amino acid residues with a predicted molecular weight of 55.57 kD, bioelectric point value of 9.16. Amino acid sequence analysis showed that it contains seven conserved domains named WD40 whose function is as a protein-protein or protein-DNA interaction platform. Signal peptide prediction results indicated that ScTAD1 without signal peptide and is a secreted protein. Tertiary structure prediction showed that ScTAD1 is highly similar to the homologous protein from Brachypodium distachyon (XP_003558934.1), Zea mays (XP_008650376.1) and Oryza sativa (AAN74839.1). In the phylogenetic tree, ScTAD1 has the closest evolutionary relationship with the homologous protein from Sorghum bicolor (XP_002468612.1). The qPCR analysis showed that ScTAD1 expressed in all the tested tissues, but high expression mainly occurred in tiller buds, followed by leaves, leaf sheath, and the lowest in root. At the different stages of axillary buds development, high expression of ScTAD1 gene appeared in tender buds; when the seedling was treated with IAA and 6-BA, high expression occurred in 36 h, but reduced in 48 h in 6-BA treatment, which implied that this gene can be regulated by the two plant hormones. 【Conclusion】 The ScTAD1 was successfully cloned from sugarcane, and it expressed in different sugarcane tissues with the highest expression in tiller buds. The gene ScTAD1 may play an important role in regulating the development of sugarcane axillary buds, and its expression can be regulated by the auxin and cytokinin.
    TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY·AGRICULTURE INFORMATION TECHNOLOGY
    Effects of Shading at Grain Filling Stages on Starch Components and Physicochemical Properties of the Waxy Wheat and Non-Waxy Wheat
    LIU XiWei, ZHANG Min, ZHANG YuChun, YANG Min, SONG XiaoJun, CAI RuiGuo
    Scientia Agricultura Sinica. 2017, 50(9):  1582-1593.  doi:10.3864/j.issn.0578-1752.2017.09.004
    Abstract ( 410 )   HTML ( 5 )   PDF (456KB) ( 416 )   Save
    References | Related Articles | Metrics
    【Objective】The objective of this experiment is to comprehensively study the effects of shading at grain filling stage on physicochemical properties of waxy wheat and non-waxy wheat starch, and reveal the intrinsic relationship between the starch components and physicochemical properties of wheat starch. 【Method】In fields, waxy wheat cultivar Nongdanuo 50222 and non-waxy wheat cultivar Lunxuan 987 were used as the material to investigate the effects of shading at grain filling stage on starch components and physicochemical properties. The photosynthetic active radiation was cut off by 60% at early grain filling stage (1-10 d), middle grain filling stage (11-20 d) and later grain filling stage (21-30 d), the natural condition was taken as the control (CK). 【Result】The content of total starch, amylose and amylopectin were decreased significantly after shading at grain filling stage, the effect of shading at early grain filling stage was maximum, while later grain filling stage was minimum, and starch content of Lunxuan 987 was much more sensitive to shading than Nongdanuo 50222. The amylose/amylopectin ratio of Lunxuan 987 was increased at each shading treatment during the grain filling, while Nongdanuo 50222 was decreased at the early and middle grain filling stages. The B-granules volume, surface and number proportion of Lunxuan987 increased significantly, and those of A-granules decreased after shading at early and later grain filling stages. The B-granules volume, surface and number proportion of Nongdanuo 50222 were increased, while those of A-granules decreased at each shading stage. The relative crystallinity of starch was decreased after shading at grain filling stage, and with the shading delaying, the effects on relative crystallinity were decreased. But the relative crystallinity of Nongdanuo 50222 starch was significantly greater than Lunxuan 987. The peak viscosity, valley viscosity, final viscosity and breakdown value of the Lunxuan987 starch were decreased after shading at early and middle grain filling stages. While the above indexes of Nongdanuo 50222 starch were decreased and significantly higher than Lunxuan 987 starch at each shading stage. Correlation analysis showed that the amylose content and the amylose/amylopectin ratio were negatively correlated with the final viscosity, setback value, peak viscosity, valley viscosity and pasting time. The amylopectin content was positively correlated with the above indexes. The B-granules volume proportion was negatively correlated with the final viscosity and setback value. The B-granules surface proportion had a significant positive correlation with relative crystallinity, final viscosity, setback value and pasting time, and was negatively correlated with pasting temperature. 【Conclusion】Shading at different grain filling stages changed the wheat endosperm starch composition, granule size distribution, relative crystallinity and pasting parameters. There were significant correlations between wheat endosperm starch components and physicochemical properties, which indicated that the effects of shading on starch components indirectly affected the physicochemical properties of wheat.
    3D Shape Simulation of Winter Wheat after Turning Green Stage Based on Effective Accumulated Temperature
    LI ShuQin, ZHU YePing, LIU HaiLong, LI ShiJuan, LIU ShengPing, ZHANG HongYing, GAO Wei
    Scientia Agricultura Sinica. 2017, 50(9):  1594-1605.  doi:10.3864/j.issn.0578-1752.2017.09.005
    Abstract ( 304 )   HTML ( 2 )   PDF (574KB) ( 420 )   Save
    References | Related Articles | Metrics
    【Objective】Based on effective accumulated temperature, the aim of this study is to realize combination of wheat growth model and shape model using 3D modeling technology, express environmental factors influence on wheat growth and morphological structure, finally realize the 3D visualization in the process of wheat growth, provide important reference for wheat crop growth dynamic prediction, cultivation management control and crop plant type design.【Method】As the main commercial wheat varieties in Tianjin region, Hengguan35, Jimai22 and Heng4399 were used as the experimental materials in this study, the field experiments of different varieties and nitrogen levels were carried out in 2015-2016 growth reasons of winter wheat, winter wheat shape data were collected under different nitrogen levels. After analysis of quantitative relationship among various varieties of winter wheat morphology data and effective accumulated temperature, simulation models of winter wheat leaf length and maximum leaf width were constructed using Logistic equation. Based on simulation models, every day shape data of various varieties of winter wheat were calculated. With the help of OpenGL and NURBS surface modeling technology, winter wheat geometry model was built. Finally, combination of winter wheat growth model and shape model was realized, and growth process visualization of winter wheat after turning green stage was realized.【Result】Under the different varieties and different nitrogen levels, R2 of leaf length regression equation was between 0.772-0.983, F was between 10.153-340.191, and Sig was less than 0.05, R2 of maximum leaf width regression equation was between 0.853-0.999, F was between 17.371-4 359.236, and Sig was less than 0.05, the results showed that the model fitting degree and significance were better. After data validation, absolute error of leaf length model was between 0-3.88 cm, root mean squared error (RMSE) was between 0.24-1.95 cm, absolute error of maximum leaf width model was between 0-0.28 cm, and RMSE was between 0.02-0.15 cm. It is indicated that the simulation models had high precision, and the models had a good predictive ability for different varieties of winter wheat leaf growth. Based on simulation models, every day shape data of winter wheat was calculated, plant morphology of different varieties under different nitrogen levels was constructed, and growth process after turning green stage was realistically simulated. 【Conclusion】The winter wheat leaf length and maximum leaf width simulation model after turning green stage was built based on the effective accumulated temperature, which could predict winter wheat leaf growth state after turning green stage, could realize combination of wheat growth model and shape model, and could implement leaf growth visualization of different varieties of winter wheat under different nitrogen levels.
    Spatial-Temporal Variations of Yield Gaps of Spring Maize in Northeast China
    LIU ZhiJuan1, YANG XiaoGuang1, Lü Shuo1, WANG Jing1,2, LIN XiaoMao3
    Scientia Agricultura Sinica. 2017, 50(9):  1606-1616.  doi:10.3864/j.issn.0578-1752.2017.09.006
    Abstract ( 363 )   HTML ( 4 )   PDF (2071KB) ( 648 )   Save
    References | Related Articles | Metrics
    【Objective】 As the population increase, climate change and the environmental issues become increasingly prominent, food production and food security issues have attracted extensive attention. However, at present, the yields of crops are much lower than potential yields, therefore, how to produce enough food on limited land resources has become the major agricultural problem in China. Northeast China (NEC) is one of the most important maize production areas in China, where the maize output accounts for about 29% of the nation’s production. Therefore, increasing maize yield has undoubtedly played a vital role in securing food production in China. 【Method】 The yield gap between the potential yield and actual farmers’ yields of maize in Northeast China was studied on the basis of meteorological data, agro-meteorological observations, and agricultural statistical data during the period from 1961 to 2010, and by using the Agricultural Production System Simulation Model (APSIM-maize) and statistical method, which will provide a scientific basis for the ascension of crop production in NEC. 【Result】 The yield gap between potential and actual farmers’ yields (total yield gap) of spring maize decreased with increasing latitudes and longitudes (P<0.01). Among locations, this yield gap ranged from 4.8 t·hm-2 to 11.9 t·hm-2. The yield gaps between potential and attainable yields (yield gap 1), attainable and potential farmers’ yields (yield gap 2) showed a decreasing trend with increasing longitudes, showed a negative relationship with precipitation during the growing season. Among locations, mean yield gap 1 ranged from 0.06 t·hm-2 to 3.2 t·hm-2. And mean yield gap 2 ranged from 1.7 t·hm-2 to 8.0 t·hm-2, mainly due to the effects of management practices. The mean weighted yield gap between potential and actual farmers’ yields was 64% of the potential yield of spring maize. Moreover, 8%, 40%, and 16% reductions in potential yields were due to non-controllable factors, agronomic factors, and socioeconomic factors, respectively. During the past five decades, the yield gap of these four levels all showed a decreasing trend, total yield gap and yield gap 3 decreased by 1.55 t·hm-2, and 1.40 t·hm-2 per decade (P<0.01) in NEC, However, yield gap 1 and 2 showed no significant trend. 【Conclusion】 It was concluded that the yield gap between potential and actual farmers’ yields of spring maize decreased with increasing latitudes and longitudes, moreover, agronomic factors are the main constraints limiting maize yield in NEC, the yield gap could be deeply reduced by 40% by improving agronomic factors, including local management practices, soil conditions, and high-yielding varieties.
    PLANT PROTECTION
    Occurrence of Grey Mould Disease in Greenhouse-Grown Strawberry and Its Correlations with Epidemic Factors in Hubei Province
    GAO CuiZhu, YANG HongLing, HUANGXIA YuQi, HUANG JunBin, LI GuoQing, ZHENG Lu
    Scientia Agricultura Sinica. 2017, 50(9):  1617-1623.  doi:10.3864/j.issn.0578-1752.2017.09.007
    Abstract ( 265 )   HTML ( 3 )   PDF (382KB) ( 665 )   Save
    References | Related Articles | Metrics
    【Objective】Strawberry grey mould is an important fungus disease worldwide. The objectives of this study are to explore the development of Botrytis cinerea in greenhouse in Hubei Province, analyze the relationship between different epidemic factors and disease rates of grey mould. Significant correlation factors were selected and used to build a model, and to provide a theoretical foundation for prevention and control of strawberry grey mould in greenhouse in Hubei Province. 【Method】 From 2013 to 2015, three representative strawberry greenhouse in strawberry planting base of Hubei Province Academy of Agricultural Sciences were selected in this study. A method of five sampling points was used for collecting leaves, flowers and fruits, and infection rates of B. cinerea on plant tissues were detected by specific PCR and moisture culture methods. The data of two greenhouses were selected to analyze the relationships between disease rate of strawberry fruits and disease rates of flowers and leaves, temperature, relative humidity, infection rates of fruits, flowers and leaves by Pearson correlation analysis. Disease rates of leaves (x2), temperature (x3), infection rates of fruits (x5) were significantly related to the incidence of disease on strawberry fruit and were used as the dependent variables (y). And the factor x2, x3 or x5 was used as independent variable to multiple linear regression equation by linear regression method to establish the regression models for the greenhouse variables (x2,x3, x5) and strawberry fruit incidence (y), respectively. The predicted values of strawberry fruit incidence were calculated by the regression model, and the predicted values were compared with the actual values in the third greenhouse. 【Result】In 2013-2015, the changes of infection rates of flowers, leaves and fruits were significantly different. Infection rates of flowers and fruits were relatively high and the infection rates were 0-53.33% and 0-86.00%, respectively. The beginning time of disease on different tissues were not the same. The strawberry grey mould was found on fruits, flowers and leaves from early December, mid-late December and early January or February, separately. The occurrences of disease on flowers and leaves were light and stable, and the fruit disease gradually increased after March with the highest disease rate of 80.07%. The disease rate of strawberry leaves, temperature and fruit infection rate were significantly correlated with disease rate of fruit (P<0.01). Regression models for strawberry fruit incidence rate and different epidemic factors was established as y=0.55x5+5.76 (R2=0.645, P<0.01) (model 1), y=8.18x2+9.25 (R2=0.498, P<0.01) (model 2) and y=2.49x3-13.62 (R2=0.446, P<0.01) (model 3), respectively. The predicted values and the actual values were analyzed by regression analysis. The results showed that the correlation between the actual fruit incidence and the predicted incidence in model 1 was the best. 【Conclusion】 In strawberry greenhouses in Hubei Province, fruit disease rate was affected significantly by the fruit infection rate, disease rate of leaf, and temperature. Removal of diseased tissues and reduction of disease infection on fruits are useful methods for control of grey mould.
    Film Formation and Biological Properties of 40% Thiamethoxam·Pyraclostrobin Flowable Concentrate for Seed Coating
    QI Lin, WANG YuXiang, WANG Ning, DUAN YiMing, ZHANG Ying, WANG Ya, XIAO LuLu, LI XiaoGang
    Scientia Agricultura Sinica. 2017, 50(9):  1624-1634.  doi:10.3864/j.issn.0578-1752.2017.09.008
    Abstract ( 362 )   HTML ( 1 )   PDF (1468KB) ( 675 )   Save
    References | Related Articles | Metrics
    【Objective】As we all know, seed coating has become an important means of crop disease and pest control. It can effectively and efficiently control pests and diseases at seedling stage, improve the efficacy of pesticides, reduce the number of drugs, reduce labor and so on. In order to broaden the application of flowable concentrate for seed coating (FSC) in precise control of rice diseases and insect pests, 40% thiamethoxam-pyraclostrobin flowable concentrate for seed coating was prepared based on the film-forming agent, and the stability and safety of rice seed coating were systematically evaluated.【Method】The formulation of diacetone acrylamide-butyl acrylate copolymer was prepared by emulsion polymerization. The formulation of 40% thiamethoxam·pyraclostrobin flowable concentrate for seed coating was optimized, and prepared through the wet milling process. The film-forming agents were characterized by water-resistance and film-forming stability, and the quality indexes of seed coating were tested. At the same time, the biological properties of rice seedling treated with seed coating agent were evaluated by pot experiment, and the optimum dose was determined by laboratory test. Root length, plant height, root number, leaf number, root activity, chlorophyll, free proline, antioxidant enzyme were also evaluated.【Result】Diacetone acrylamide-butyl acrylate copolymer film had a good film-forming stability, and the changes of water absorption and resistance in the seed coating were observed by optical microscope. The membrane was dissolved slowly in water, until 35 d, there were small changes in its damage area and porosity. The optimum formulation of 40% thiamethoxam·pyraclostrobin flowable concentrate for seed coating was 25% of thiamethoxam, 15% of pyrazolemcetate, 0.5% of quick T, 8% of FS 3000, 0.3% of magnesium aluminum silicate, 0.12% of xanthan gum and 0.5% of bentonite, 5% of ethylene glycol and 5% of Haishu Liquid Red 2R. The suspension rate of FSC was 97.90%, film formation time was 12 min, with good film formation and dispersion. The coating uniformity was 88.23%, viscosity was 0.53 Pa·s, the drop rate of 3.25%, with good cold and thermal storage stability. All the indicators of the flowable concentrate for seed coating met the relevant suspension seed coating quality standards. The germination rate of rice seeds increased by 31.98% compared to CK and by 6.57% compared to the positive control, plant height increased by 6.48% and 9.42% compared to the positive control, root activity increased by 38.07% and 24.20% compared to the positive control, and chlorophyll content increased by 143.02% and 78.63% compared to the positive control, free proline content increased by 28.70% and 23.79% compared to the positive control. And the effect on antioxidant enzyme activity was not significant, SOD enzyme activity increased by 30.69% compared to CK and by 15.66% compared to the positive control, changes of POD and CAT enzyme activity was not significant, using a drug ratio of 1﹕50 (2.88 g a.i/kg) treatment.【Conclusion】40% thiamethoxam·pyraclostrobin flowable concentrate for seed coating has good film-forming properties, long persistence period, high germination rate, and safe for rice seed, which could provide a powerful guarantee for the seedling growth of rice.
     
    SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT
    Differences in Maize Yield Responses to Phosphorous Fertilizer in Different Ecological Zones of Jilin Province
    WANG Yin, GUO Dan, GAO Qiang, LI CuiLan, YAN Li, FENG GuoZhong, LIU ZhenGang, FANG Jie
    Scientia Agricultura Sinica. 2017, 50(9):  1635-1645.  doi:10.3864/j.issn.0578-1752.2017.09.009
    Abstract ( 222 )   HTML ( 4 )   PDF (4252KB) ( 387 )   Save
    References | Related Articles | Metrics
    【Objective】This study aimed to estimate differences in the effects of P fertilizer application on maize yield increases among the different ecological zones and counties of Jilin province, and further to improve yield level and P fertilizer efficiency by optimizing regional P fertilizer management and allocation. 【Method】A total of 1 110 maize “3414” field experiments were conducted in Jilin province during 2005-2013, the data of the -P (No P fertilizer applied) and +P (P fertilizer applied as recommended) treatments in these experiments were collected in this study, and the indexes such as yield increase, agronomic efficiency (AE) and fertilizer contribution rate (FCR) of P fertilizer were calculated at regional and county levels, aiming to compare maize yield response to P fertilizer among the ecological zones. Moreover, the relationships between maize yield in +P treatment, FCR and the yield in -P treatment were established to investigate the effects of soil indigenous P supply on P fertilizer responses of maize yield among different ecological zones.【Result】The results showed that P fertilizer application played an important role for ensuring high yield in recent maize production of Jilin province. The yield response to P fertilizer was 1.4 t·hm-2 (18.4%) in the eastern humid mountainous area (EHMA), 1.2 t·hm-2 (14.5%) in the central semi-humid plain area (CSPA) and 1.7 t·hm-2 (24.7%) in the western semi-arid plain area (WSPA), respectively. Under current optimal P application rate condition, the averaged 23.2 kg·kg-1 for AE of P fertilizer being in the EHMA, the averaged 17.5 kg·kg-1 being in the CSPA, and the averaged 24.1 kg·kg-1 being in the WSPA; and the values were 14.6%, 11.9%, and 18.3% for FCR of P fertilizer in the three ecological zones, respectively. The results of statistical analysis suggested that maize yield response and FCR of P fertilizer were higher in the WSPA than those in the EHMA and CSPA, while AE was higher in WSPA and CSPA than that in the EHMA. Across all the ecological zones, significant positive and linear correlations were observed in maize yields between -P and +P treatments, the model equation was y =0.855 x + 2605(R2=0.697**) in the EHMA, y=0.846 x + 2658(R2=0.739**) in the CSPA and y=0.761 x + 3545(R2=0.623**) in the WSPA. Meanwhile, significant negative and logarithmic correlations were observed between FCPs of P fertilizer and maize yields in -P treatment, these model equations were y= -21.8 ln(x) + 211.7(R2=0.248**), y= -18.8 ln(x) + 183.3(R2=0.230**) and y = -26.7 ln(x) + 257.4(R2=0.342**) in the three ecological zones, respectively. With the increasing maize yield in -P treatments, WSPA showed higher magnitude of change in maize yield increase in +P treatment but lower performance in FCR of P fertilizer than the other ecological zones.【Conclusion】In conclusion, P fertilizer response to maize yield was significantly affected by ecological zones due to natural environment characteristics and soil fertility, and thereby P fertilizer should be allocated and managed appropriately in the crop production based on regional soil indigenous P supply and crop response to P fertilization. Compared with EHMA and CSPA, soil indigenous P supply was relatively lower in the WSPA whilst greater yield increases were observed when P fertilizer was applied. For the maize production in Jilin province, P fertilizer management and adjustment should receive more attention in the WSPA than the other ecological zones, and also should combine with other cultivation management practices to improve yield level and fertilizer use efficiency simultaneously.
    Changes in Soil Properties and Accumulation of Soil Carbon After Cultivation of Desert Sandy Land in a Marginal Oasis in Hexi Corridor Region, Northwest China
    SU YongZhong, ZHANG Ke, LIU TingNa, FAN GuiPing, WANG Ting
    Scientia Agricultura Sinica. 2017, 50(9):  1646-1654.  doi:10.3864/j.issn.0578-1752.2017.09.010
    Abstract ( 279 )   HTML ( 7 )   PDF (710KB) ( 649 )   Save
    References | Related Articles | Metrics
    【Objective】Changes in soil nutrients and process of soil carbon accumulation following the conversion of desert sandy land to irrigation cropland in arid region in northwest China is an important indicator for evaluating oasis ecosystem structure, function and productivity evolution. It is also one of the aspects for understanding soil development process and its evolution patterns on the newly cultivated farmlands in arid region.【Method】In this study, the temporal changes in soil physical and chemical properties in the 0-60 cm soil layers were determined in a 0-46 year cultivation sequence in the Linze marginal oasis. Soil properties in the plough layer (0-20cm) between 2008 and 2014 were compared to determine the changes of soil properties within the recent 6 years.【Result】The results indicated that sand content in the 0-20cm surface layer showed a consistent decreasing pattern with increasing duration of cultivation, but significant changes in particle size distribution only occurred in soils cultivated for more than 16 years. Within the recent 10 years, no significant changes in soil particle size distribution were detected. As cultivation time increased, soil organic carbon (SOC), total N and available N and P concentrations all increased. SOC and total N showed a rapid and linear increase in the initial 20 years after cultivation, and thereafter, had a slow increase. SOC, total N, and available N and P concentrations increased by 9.0 times, 6.3 times, 6.3 times and 13.5 times, respectively, after 46 years of continuous cropping. Soil inorganic carbon (SIC) increased by 77.1% after cultivation of 46 years. Available K concentration showed a decrease in the initial 20 years of cultivation, and subsequently, had a rapid increase. Also, SOC, N, P and K concentrations in the 20-40 cm and 40-60 cm soil layers gradually increased with increasing cultivation time, but the increase extent was far less than that of surface soil. During the 6 years period from 2008 to 2014, no significant changes in soil particle size distribution in the plough layer were found, however, SOC, N, P and K nutrients showed a distinct accumulation. After 46 years of continuous cropping, SOC, SIC and total C sequestration rate was 0.75, 0.79 and 1.47 kg·hm-2·a-1, respectively. SOC accumulation occurred mainly in the surface soil, SIC accumulation was found in the 40-60 cm soil layer. Conversion of sandy desert soils to irrigation croplands had a tremendous soil carbon sequestration potential. The increased silt and clay content play an important role in SOC and nutrients accumulation and retention.【Conclusion】After cultivation of native sandy lands and subsequently, continuous cropping improved significantly soil fertility. However, soil fertility was still in a low status after 46 years of cropping. Therefore, improved agricultural management is imperative to accelerate soil fertility improvement and maintain long-term productivity of the newly reclaimed sandy farmlands.
    HORTICULTURE
    Assembling and Characteristic Analysis of the Complete Chloroplast Genome of Vitis vinifera cv. Cabernet Sauvignon from High-Throughput Sequencing Data
    XIE HaiKun, JIAO Jian, FAN XiuCai, ZHANG Ying, JIANG JianFu, SUN HaiSheng, LIU ChongHuai
    Scientia Agricultura Sinica. 2017, 50(9):  1655-1665.  doi:10.3864/j.issn.0578-1752.2017.09.011
    Abstract ( 389 )   HTML ( 4 )   PDF (1479KB) ( 1218 )   Save
    References | Related Articles | Metrics
    【Objective】 A method was built to assemble complete chloroplast (cp) genome of Vitis and analyze its characteristics with Vitis vinifera cv. Cabernet Sauvignon, which will provide a methodological guidance for evolution and phylogenetic analysis of vitis in the future.【Method】Total genomic DNA was extracted from young leaves of Cabernet Sauvignon using plant genomic DNA kit. The small fragments (350 bp) of DNA libraries were constructed according to the manufacturer’s manual for the Illumina HiSeq PE150, and the sequencing depth was 10 fold. Grape cp reads were extracted by BLASTN software according to cp genome sequence of Arabidopsis thaliana (NC000932) and Pinot Noir (DQ424856). SOAPdenovo 2.04 assembled the extracted cp reads into complete chloroplast genome of Cabernet Sauvignon. Then its basic characteristics were analyzed using some bioinformatic softwares. 【Result】 This research obtained total of 5.2 G raw data after high-throughput sequencing. Among them, 0.42 G clean data of grape cp reads were extracted, and it accounted for about 8%. These extracted grape cp reads assembled the complete cp genome successfully. The characteristic analysis of grape cp genome showed that it was a circular molecule of 160 676 bp in length with a typical quadripartite structure, including a pair of inverted repeats (IRA and IRB) of 26 235 bp that were separated by large and small single copy regions (LSC and SSC) of 89 134 bp and 19 072 bp, respectively. A total of 154 predicted genes, including 99 protein-coding genes, 47 tRNA genes and 8 rRNA genes were identified. And the GC content of cp genome was 37.43%. Furthermore, the cp genome of Cabernet Sauvignon contained 37 tandem repeat sequences and 53 dispersed repeats. The length of most tandem repeat sequences was 11-42 bp. They accounted for 0.83% of whole cp genome, and the dispersed repeats accounted for 5.33%. Additionally, fifty short simple repeats (SSRs) loci of cp genome were detected. And most SSR loci were composed of A or T contributing to an obvious bias in base composition. Distribution of cp SSRs was non-uniform because the regions of LSC, SSC, and IR were located by 39, 7, and 4 SSRs, respectively. The codon usage of protein-coding genes was biased to use A/T bases. And among these codons, leucine (L) and cysteine (C) were the most and least used amino acids, respectively. The phylogenetic analysis showed that Cabernet Sauvignon had a closer genetic relationship with Pinot Noir, V. aestivalis and V. rotundifolia.【Conclusion】Based on high-throughput sequencing, the complete cp genome of Cabernet Sauvignon was obtained successfully. Cp and cpDNA were not required to isolate and extract in this method which shortened the experiment time, reduced the labor intensity and improved the feasibility. The subsequent characteristic analysis showed that gene structure, gene order, GC content and codon usage were identical with typical angiosperm. This research provided perfect and detailed data for the study of cp genome of Vitis vinifera, which also supplemented many deficiencies of characteristic analysis of cp genome of Vitis, such as repeat sequences, codon bias and SSRs.
    Study on Phylogeny of 240 Mandarin Accessions with Genotyping-by-Sequencing Technology
    WANG XiaoKe, JIANG Dong, SUN ZhenZhu
    Scientia Agricultura Sinica. 2017, 50(9):  1666-1673.  doi:10.3864/j.issn.0578-1752.2017.09.012
    Abstract ( 480 )   HTML ( 22 )   PDF (1883KB) ( 962 )   Save
    References | Related Articles | Metrics
    【Objective】Genotyping-by-sequencing (GBS) is an economic technique to discover SNP and genotype myriad of crop germplasms in an effective way. The aim of this study is to clarify the classification and evolution of 240 mandarin germplasms by using GBS. 【Method】 A total of 240 mandarin germplasms conserved in the National Citrus Germplasm Repository in Chongqing, with widely genetic diversity and geographic origin, were selected as trial materials. GBS library was constructed with genomic DNAs after digested with EcoR I restriction endonuclease and sequenced on Illumina HiSeq PE150, then the sequences were mapped to the clementine (Citrus clementina hort. ex Tanaka) reference genome by using BWA, and SNPs were called with the SAMTOOLS pipeline. With the SNPs genotyping data, a phylogenetic tree was built by using Neighbor-joining method and a principal component analysis (PCA) was carried out. 【Result】By using GBS, a total of 96.3 Gb of sequences were generated from the 240 mandarin germplasms, and each sample produced 401.26 Mb in average. After screening with parameter of dp4, miss0.2 and minor alleles frequency (MAF)0.01, a total of high quality 114 200 SNP sites were retained. The PCA analysis showed that the 240 mandarin germplasms could be divided into 4 groups, in which satsuma sub-group and wild mandarin sub-group could be clearly separated from other mandarin accessions. With phylogenetic analysis, the 240 mandarin germplasms could be divided into 11 groups. Both the phylogenetic analysis and PCA suggested that the genetic variations were presented in mandarin germplasms with different geographical origins and morphological characteristics. For example, satsuma mandarin (Citrus unshiu Macf.) derived from Japan, clementine (Citrus clementina Hort.ex. Tanaka) and its offspring from Europe and America, as well as wild mandarins from China could be clearly distinguished based on phylogenetic tree, moreover the phylogenetic tree showed that the mandarin germplasms derived from the Southern and Northern of China have unique evolutionary route. The wild mandarins distributed in Nanling Mountain and southern China have a closer phylogenetic relationship with sour mandarin (Citrus sunki Hort.ex Tanaka) and Shatang ju mandarin, which are widely cultivated in southern China nowadays, whereas the evolution of mandarins in the northern of China were related to some primitive and old cultivars. In addition, hybrid breeding, long-term artificial selection and domestication led to the subdivision formation and increased the genetic diversity of mandarin. Besides, results of this study showed that GBS has a potential advantage to identify some mandarin accessions with suspicious parents. For example, the phylogenetic tree clearly shows that “Or” tangor has a very close relationship with Kinnow mandarin. 【Conclusion】GBS technology provides an effective and high feasible approach to assistant the taxonomic classification of 240 mandarin accessions, the classification results are in accordance with the conclusion based on morphological method. Meanwhile GBS also is a powerful tool for germplasm identification, and can be applied in the new cultivars identification and intellectual property protection.
    Influence of Heat Stress on the Expression of Related Genes and Proteins in Grapevines
    ZHA Qian, XI XiaoJun, JIANG AiLi, TIAN YiHua
    Scientia Agricultura Sinica. 2017, 50(9):  1674-1683.  doi:10.3864/j.issn.0578-1752.2017.09.013
    Abstract ( 316 )   HTML ( 2 )   PDF (1547KB) ( 348 )   Save
    References | Related Articles | Metrics
    【Objective】The suitable air temperature is necessary for growth of grapes. Heat stress often happens in south area of China during grape mature period. The industrial economic benefits of grape are affected by the water-lost leaves and sunburn fruits. So study on the responsive mechanism of grapevines under high temperature stress is particularly important. The present research is mainly focused on the high temperature stress response of young grapes under control condition. As studies on response to high temperature stress in adult grapes are limited, so detailed explanation of high temperature damage in grapevines at different ages could provide a theoretical foundation for prevention of high temperature adversity. 【Method】 This study used 8 table grape varieties in south area of China as experimental materials, including Zuijinxiang, Summer Black, Kyoho, Jumeigui, Shenyu, Shenhua, Shenfeng, and Hupei 1#. Young grapevines (1-year-old) at the same growth stage were acclimated for 7 days in a controlled environment room, with a photoperiod of 14 h light under cool-white fluorescent light at 100 μmol·m-2·s-1. The grape plants were divided into 3 groups and were acclimated for 7 days at normal temperature (25℃). On the following day, 1 group of grapevines was kept at 25℃ in this controlled environment room. The other 2 groups were treated at 35℃or 45℃, respectively, from 10:00 h to 16:00 h (which was stimulated the high temperature levels in the day). The heat response was tested at 0, 3 h, 6 h and 150 h. In addition, the 6-year-old adult grapevines were selected to study heat stress response under field conditions in the present experiment, July 23, 2015 (denoted as “37℃”; highest temperature <40℃) stood for pre-temperature stress and July 31, 2015 (denoted as “42℃”, highest temperature >40℃) stood for post-temperature stress. 【Result】 The phenotype of young grapevines under high temperature stress was observed. The young sprout and aging leaves of Shenyu, Summer Black and Shenhua showed lightly water-loss at the beginning of high temperature stress, and recovered at 150 h. The leaves of Kyoho and Jumeigui showed slightly water-loss at 3 h and seriously water-loss at 6 h under high temperature stress. The leaves of Shenfeng, Hupei 1# and Zuijinxiang showed a seriously water-loss at 3 h, and the leaves of whole plant dry rot at 6 h under high temperature stress. And different temperature treatments (35℃/45℃/42℃) induced the expression of resistance genes in young and adult grapevines. However, the expression of genes in levels were different. The higher temperature level induced the greater gene expression. In addition, the expression of GLOS1 and HSFA2 in Shenyu, Shenhua, Zuijinxiang, Kyoho, and Jumeigui and the expression of HSP70 in Shenyu, Shenhua, Summer Black, and Kyoho recovered to the original levels at 6 h/150 h after high temperature treatments. The expression of HSP17.9 was increased by high temperature stress and the expression was not decreased with the prolongation of time. High temperature treatments (45℃/42℃) induced the expression levels of HSP21 protein in young and adult grapevines, however, the expression levels of HSP21 protein decreased in some varieties (Shenfeng and Zuijinxiang). 【Conclusion】 It was found that there are differences between different grape cultivars in the tolerance to high temperature stress. Firstly, Shenyu, Shenhua, and Summer Black are more tolerant to high temperature than others. Secondly, the system of heat-tolerance in Kyoho and Jumeigui collapsed. And then, Shenfeng, Hupei 1# and Zuijinxiang belong to the heat-sensitive grape cultivars. In addition, the differences of expression of genes and proteins between the grape seedling and adult trees were due to the tree age and the happening way of high temperature stress.
    Molecular Basis of the Effects of Nitrate Signal on Root Morphological Structure Changes of Chrysanthemum
    GUO YunHui, YU YuanYuan, WEN LiZhu, SUN CuiHui, SUN XianZhi, WANG WenLi, SUN Xia, ZHENG ChengShu
    Scientia Agricultura Sinica. 2017, 50(9):  1684-1693.  doi:10.3864/j.issn.0578-1752.2017.09.014
    Abstract ( 288 )   HTML ( 2 )   PDF (1323KB) ( 592 )   Save
    References | Related Articles | Metrics
    【Objective】 In order to reveal the root morphology and molecular basis of the response of nitrate nitrogen to root development of chrysanthemum, and provide a basis for chrysanthemum breeding to improve the efficiency of nitrogen, this study was carried to investigate the changes of root morphology and structure, the contents of nitrate nitrogen and endogenous hormones, the nitrate nitrogen transport genes and root formation gene of chrysanthemum. 【Method】 The rooted cuttings of chrysanthemum were used in water-culture system in this experiment, then treated by 10 mmol·L-1 KNO3 while control was treated with Hogland nutrient solution without nitrogen. On the day 0, 1, 3, 7, 14, 21 and 28 after treatment, anatomical structures were observed, the contents of NO3-, IAA and CTK in the roots and leaves were measured, the cDNA conserved sequence fragments of CmNRT1.1, CmNRT2.1, CmNAR2.1 which were identified as the NO3- transport protein genes and CmANR1 which were identified as the lateral root differentiation gene of the roots were cloned, and the relative expression levels of them were observed using quantitative real-time PCR. 【Result】The results showed that: There were no significant differences were observed in the overall length, average diameter, total surface area and total volume of roots between NO3- treatment and control within the first 3 days, they were increased significantly after 7 days compared with those of control. The cross sections of roots were also observed on the day 28 after treatments. The vascular bundle diameter of the 1st root, 2nd root and 3rd root after NO3- treatments were increased significantly compared with those of control. The ratios of vascular bundle to root diameter of the 1st root, 2nd root and 3rd root were significantly increased compared with those of controls. The NO3- contents of chrysanthemum reached the peak on the day 7 (0.45 mg·g-1 FW) in the roots and on the day 14 (0.35 mg·g-1 FW) in the leaves, respectively, then both of them decreased slightly, but they were maintained higher level compared with those of control on all days. Compared with those of control, the contents of IAA and CTK in roots and leaves in the NO3- treatments were significantly increased. The peaks of the contents of IAA and CTK in the roots appeared on the day 7 and those of in the leaves appeared on the 14 day after treatments, while the IAA and CTK contents of controls showed no significant change. The relative expression levels of CmNRT1.1 gene’s peak were appeared on the 1 day after treatment (the control also on the day 1). The relative expression levels of CmNRT2.1 and CmNAR2.1’s peaks were appeared on the day 3 after treatment (the control slightly increased on the day 3 and remained relatively stable). While the relative expression levels of CmANR1 reached the peak on the day 7 after treatment (the control on the day 14), and the relative expression levels of the 4 genes maintained higher levels than those of control throughout the experiment. The results showed that the 4 genes were induced by nitrate, and their expression trends were similar, which were increased at first, decreased later and then remained relatively stable. 【Conclusion】 The roots of chrysanthemum could respond to nitrate signal in the growth medium. The response is realized through the expression of nitrate transporter genes and lateral root development gene, and then adjust the configuration of the roots to improve the absorption and utilization of nitrate in chrysanthemum roots.
    FOOD SCIENCE AND ENGINEERING
    Antitumor Effect of Violacein Against HT29 by Comparative Proteomics
    LIU Lu, LU Jing, WANG Ying, PANG XiaoYang, XU Man, ZHANG ShuWen, Lü JiaPing
    Scientia Agricultura Sinica. 2017, 50(9):  1694-1704.  doi:10.3864/j.issn.0578-1752.2017.09.015
    Abstract ( 325 )   HTML ( 7 )   PDF (1654KB) ( 542 )   Save
    References | Related Articles | Metrics
    【Objective】The objective of this experiment is to investigate proteomic profile of HT29 treated with high-dosage-violacein and low-dosage-violacein, and to analyze its involved metabolic pathway and mechanism. 【Method】Cytotoxic activity of violacein was analyzed by MTT assay and observed by using transmission electron microscopy. After that, the total protein was extracted from the cells.To obtain relative abundance of peptides information, total proteins labeled with multiple iTRAQ stable isotopes were segregated and analyzed with RP-LC-MS /MS. The differential expression proteins were identified through NCBI. Human. protein database. The metabolic pathway was analyzed through Go analysis and KEGG analysis. 【Result】 Violacein inhibited the growth of HT29 in dose-dependent and time-dependent manner. Compared with 5-Flu, 5 mg·L-1 violacein resulted in 50% inhibition of HT29. Its dosage was one sixth of the dosage of 5-Fu. With the increasing violacein, vacuoles in the mitochondrion and membrane blebs were found under transmission electron micrograph. Violet pigment at 30 mg·L-1 induced margination of nuclear chromatin and disappearance of cell membrane. Through quantitative proteomic analysis of these three cells, 4258 proteins were identified with MS, 757 of which were differential expression proteins (fold change of protein expression≥2). Among these differential expression proteins, there were 492 proteins in cells treated with high dosage of violacein, 112 proteins in cells treated with low dosage of violacein, and 336 proteins in cells treated with 5-Fu. Analysis of enriched KEGG pathway showed that most of these differential expression proteins were involved in 50 signaling pathways, 10 of which were enriched significantly (P<0.05), such as ribosome, citrate cycle and RNA degradation. 【Conclusion】The antitumor mechanism of violacein against colon cancer cells are mainly involved in transcription and translation in cell life cycle.
    ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT
    Vicissitude of Drug Resistance and Integron-Carrying of Escherichia coli Isolated from Yak Between 2009 and 2016 in Northwest Sichuan Plateau
    CHEN ChaoXi, HE DongMei, TANG Cheng
    Scientia Agricultura Sinica. 2017, 50(9):  1705-1713.  doi:10.3864/j.issn.0578-1752.2017.09.016
    Abstract ( 260 )   HTML ( 2 )   PDF (957KB) ( 287 )   Save
    References | Related Articles | Metrics
    【Objective】Aiming at the trend of drug resistance of Escherichia coli increased year by year and the problem of antibacterial agents for diseases control and prevention in yak (Bos grunniens), 1 908 Escherichia coli isolates from feces of free-ranging yaks (including the healthy and ill yaks), gastrointestinal contents (slaughtered yaks) and viscera samples (dead yaks) were chosen for antimicrobial susceptibility testing to 27 antibacterial agents and integrase genes detection between 2009 and 2016 in this study. The results of the study will be helpful to investigation of the vicissitude of drug resistance and integron-carrying of Escherichia coli isolated from yak and provide a reference for safe medication for yak in northwest Sichuan plateau.【Method】Broth microdilution method and WHONet5.6 software were used, respectively, for minimum inhibitory concentration (MIC) determination according to the guidelines of Clinical and Laboratory Standards Institute (NCCLS) and the experimental data statistical analysis. Class 1 and class 2 integrase genes were amplified using conventional PCR for the detection of integron-carrying of class 1 and class 2 integrons. 【Result】 The results showed that: the drug resistance level to 27 antibacterial agents of the strains isolated between 2009 and 2016 kept a rising trend year by year. Except that the drug resistance level to oxytetracycline of the strains isolated between 2014 and 2016 and the drug resistance level to sulfonamides of the strains isolated between 2015 and 2016 were over 60.00%, all the other strains isolated in different years revealed lower drug resistance level to other 23 antibacterial agents and the drug resistance level to mequindox and rifampicin were lower than 30.00%, and the drug resistance rate to mequindox was lower than rifampicin between 2009 and 2016. Integron-carrying rate of Escherichia coli isolated in different years was different, 774 isolates carried at least one type of integron, accounting for 41.30% (788/1908) and 140 isolates carried both class 1 and class 2 integron, accounting for 7.34% (140/1908). Of which, 582 isolates carried class 1 integron and 346 isolates carried class 2 integron, accounting for 30.50% (582/1908) and 18.13% (346/1908), respectively.【Conclusion】The results of vicissitude of drug resistance and integron-carrying of Escherichia coli isolated from yak between 2009 and 2016 in northwest Sichuan plateau could provide a theoretical basis and experimental data for epidemiology study and screening for preventive drugs and ensure the reasonable application of antibacterial drugs in northwest Sichuan plateau.
    Adjuvant Effects of Flagellin from Non-Pathogenic E.coli on FMDV
    SUN XiaoHan, ZHANG BiCheng, ZHANG Qiang, HE KongWang, ZHANG XueHan
    Scientia Agricultura Sinica. 2017, 50(9):  1714-1722.  doi:10.3864/j.issn.0578-1752.2017.09.017
    Abstract ( 237 )   HTML ( 1 )   PDF (838KB) ( 514 )   Save
    References | Related Articles | Metrics
    【Objective】Foot and mouth disease (FMD) is highly infections and spread wide. It has brought a great harm to the world economic and social development. The current vaccination is still the main and effective means of prevention and control of this disease. To enhance FMD Virus (FMDV) antigenicity, the Flagella (F0) was modified from the non-pathogenic Escherichia coli to construct recombinant F0 protein and evaluate the single F0 protein and fusion protein F0-LTMT adjuvant effectiveness on FMDV based on the research about flagella protein adjuvants from home and abroad.【Method】Four recombinant proteins of F0, F0-LTMT, F0NC, and F0NC-LTMT were expressed, and their biological activities were detected by GM1-ELISA. The FMDV immunogen was prepared by mixing inactivated FMDV with a single recombinant F0 at 5 μg per mouse, and additional ISA 206 adjuvant was set according to the proportion to evaluate the immune effect in mice. The Balb/c mice was subcutaneously inoculated with emulsified immunogen twice at intervals of 2 weeks. Sera and feces were collected, respectively, on the day 0, 14, 21, 28, 35 and 45, and distal intestine was also collected after immunization on day 45. Titers of IgG in serum were detected by blocking ELISA kit, specific sIgA in feces and intestinal liquid by indirect ELISA to evaluate the titers.【Result】SDS-PAGE and Western blot analyses showed that four different recombinant flagellin were successfully obtained. Their biological activities were verified by GM l-ELISA. In mice no significant levels of antibodies were detected in the single FMDV immunized group compared with higher IgG titer sIgA titers in flagellin adjuvant group. Moreover, the synergistic effect of LTMT and flagellin facilitated to produce more IgG and sIgA in mice. When flagellin combined with the ISA 206 adjuvant, the titer of serum IgG increased significantly and gave extended duration. The mixed immunogen of FMDV, ISA 206 and H0NC-LTMT displayed the best antibody titers.【Conclusion】F0-LTMT provided dual adjuvant effectiveness to FMDV, induced systemic specific IgG and sIgA in mice. It is a potential mucosal adjuvant for FMDV.
    Expression Pattern and Chitin-Binding Mode Analyses of Cuticle Protein BmCPAP3-G in the Silkworm (Bombyx mori)
    ZHANG WeiWei, DONG ZhaoMing, ZHANG Yan, ZHANG XiaoLu, ZHANG ShouYa, ZHAO Ping
    Scientia Agricultura Sinica. 2017, 50(9):  1723-1733.  doi:10.3864/j.issn.0578-1752.2017.09.018
    Abstract ( 247 )   HTML ( 3 )   PDF (3631KB) ( 342 )   Save
    References | Related Articles | Metrics
    【Objective】The objective of this study is to explore the expression pattern of BmCPAP3-G and the binding mode of BmCPAP3-G with chitin, which will lay a foundation for the research of the cuticle proteins of silkworm (Bombyx mori).【Method】The sequence features of CPAP motif cuticular proteins and the conserved domains of BmCPAP3-G were analyzed by bioinformatics methods. The recombinant proteins were expressed by prokaryotic expression and purified by Ni affinity chromatography. The protein was identified by 5800 MALDI-TOF/TOF mass spectrometry, and then was used to prepare the polyclonal antibodies. The chitin-binding activity of BmCPAP3-G was verified by chitin affinity chromatography. The spatial and temporal expression patterns of BmCPAP3-G were analyzed by semi-quantitative RT-PCR and western blot. The binding mode of the domains of BmCPAP3-G with chitin was detected by using chitin affinity chromatography. 【Result】The BmCPAP3-G protein has a signal peptide consisting of 18 amino acids, the molecular weight of 27 kD and the isoelectric point of 4.82, the encoding gene located on the chromosome No.15. BmCPAP3-G protein has three ChtBD2 domains, in which cysteine and aromatic amino acid showed very high homology. the BmCPAP3-G was cloned, expressed and the active recombinant protein was purified. After being identified by mass spectrometer, the polyclonal antibody against BmCPAP3-G was prepared. The BmCPAP3-G was found to bind chitin by using chitin affinity chromatography. The spatial and temporal expression patterns of BmCPAP3-G were analyzed by semi-quantitative RT-PCR and western blot, revealing similar results at the transcriptional and protein levels. BmCPAP3-G was expressed highly in the head and cuticle, and minimally in the midgut, gonad, and silk gland. In the silk gland, BmCPAP3-G had a high expression level in the fourth molting and its expression decreased in the cuticle and silk gland as the fifth instar goes on. active recombinant proteins domain_3, domain_1-2, domain_2-3 were successfully expressed and it was found that all the domain_3, domain_1-2, and domain_2-3 could bind to chitin in vitro, but their binding abilities were different. Individual domains could bind with chitin, and two domains showed stronger chitin binding capacity than the single domain. 【Conclusion】BmCPAP3-G is a typical cuticular protein of CPAP family and may be involved in the degradation and formation process of chitin layer in the silk gland during molting stage. BmCPAP3-G could bind with chitin by a single ChtBD2 domain, and multiple domains in which makes it have stronger chitin binding capacity.
    RESEARCH NOTES
    Effect of Plant Canopy Transformation on Chlorophyll Fluorescence Characteristics and Fruit Yield and Quality in Closed Citrus Orchard
    HU DeYu, LIU XueFeng, HE ShaoLan, XIE RangJin, QIAN Chun, Lü Qiang, YI ShiLai, ZHENG YongQiang, DENG Lie
    Scientia Agricultura Sinica. 2017, 50(9):  1734-1746.  doi:10.3864/j.issn.0578-1752.2017.09.019
    Abstract ( 273 )   HTML ( 2 )   PDF (496KB) ( 457 )   Save
    References | Related Articles | Metrics
    【Objective】The effect of canopy modification on tree canopy characteristics, photosynthesis, nutrition metabolism, fruit production and quality was investigated in closed citrus orchard, with the aim to lay a foundation for tree shape modification, orchard management, agronomic trait supporting for aviation technology and so on.【Method】‘Olinda valencia’ orange of 15 years old was used in this study, which was grafted on ‘Carrizo’ Citrange (C. sinensis×P. trifoliata). The selected trees were modified to open center, hedgerow and trunk shapes, respectively, and those without any modification served as the control (CK). With them, the variation of tree canopy characteristics, leaf nutrition, chlorophyll fluorescence, fruit quality and yield per tree was evaluated.【Result】From June to September after modification, the leaf area index and mean leaf inclination were both increased in all shapes, most remarkably in open center shape, while the transmit coefficient for defuse penetration, transmit coefficient for radiation penetration as well as photosynthetical active radiation were opposite. The tree canopy characteristics were significantly different among all shapes, of which canopy transmittance was gradually increased in an order of open center shape>trunk shape>hedgerow shape>CK. The leaf fluorescence parameters including Fo, Fm and Do were all decreased in all shapes. During experimental time, the values of Fo and Fm of CK were significantly higher than those in other shapes, especially in open center shape. The RC/CSO, jPo jEo, jRo, yRo, dRo PI abs, PI total and so on were decreased in all shapes and the biggest drops were observed in CK, which obviously higher than that in open center shape. The photosystem activities in leaves, utilization efficiency of solar energy and photosynthetic capacities were all improved by tree shape modification. The contents of N, P, K and Zn in all shapes were decreased, while Ca, S, Fe, Mn and Cu were gradually accumulated. Compared to CK, the contents of N, Ca, S and Fe were higher in other modified shapes. The yield per tree was 101.1, 69.1, 89.11 and 64.65 kg, and the soluble solid content of fruits with 10.66%, 10.62%, 10.31% and 9.94% were observed in open center shape, hedgerow shape, trunk shape and CK, respectively.【Conclusion】In this study, the canopy modification in closed citrus orchard significantly improved canopy light condition, photosynthetic capacity and N content in leaves, which led to an increase in yield per tree as well as improvement of fruit quality. Of these shapes, the open center shape was better than other shape.