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Table of Content

    01 April 2010, Volume 43 Issue 7
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
    Construction and Transformation of RNAi Vector of OsVP1 for a Regulatory Gene of Pre-Harvest Sprouting in Oryza sativa
    GAO Yong-feng,LIU Ji-kai,FAN Jing,PENG Yi,HUANG Ke,ZHANG Dun-fang,LIU Yong-sheng
    Scientia Agricultura Sinica. 2010, 43(7):  1321-1327 .  doi:10.3864/j.issn.0578-1752.2010.07.001
    Abstract ( 1090 )   PDF (515KB) ( 1135 )   Save
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    【Objective】 Pre-harvest sprouting is a phenomenon that seeds germinate while still attached onto the maternal plants in the condition of cloudy and rainy weather, and is also a restrictive factor of hybrid rice production and seed propagation. The phenotype of rice pre-harvest sprouting is very similar to that of maize seed-specific vp1 mutant. VP1 gene is essential for seeds maturation and dormancy, and is also a key transcription factor of ABA signal transduction pathway. Thus, it is of great significance to effectively control the occurrence and hazard of hybrid rice pre-harvest sprouting. The aim of the current investigation is to dissect the biological function of homologous gene OsVP1 in Oryza sativa by using transgenic technology. 【Method】 To further elucidate the function of VP1, the RNA interference (RNAi) vector containing the sequence fragment of OsVP1 was constructed and introduced into rice cv. Nipponbare by Agrobacterium-mediated genetic transformation. 【Results】 Analysis of semi-quantitative RT-PCR revealed a distinct reduction of endogenous OsVP1 expression levels in RNAi transgenic lines compared with wild-type plants. Germination experiment showed that the percentage of geminated seeds from T1 transgenic plants was higher than that of wild-type plants. Under the different concentrations of abscisic acid (ABA) treatment, the inhibition of germination ratio of transgenic seeds was not significantly different when comparing with wild-type plants. Germination experiment of T2 panicles from transgenic plants showed more severe pre-harvest sprouting than wild-type plants. 【Conclusion】 RNA interference of OsVP1 gene can increase germination velocity of transgenic seeds and also lead to pre-harvest sprouting.

    Dynamic QTL Analysis of Dry Matter Accumulation in Soybean Seed at Different Developmental Stages

    HAN Ying-peng,TENG Wei-li,DU Yu-ping,SUN De-sheng,ZHANG Zhong-chen,XU Xiang-ling

    Scientia Agricultura Sinica. 2010, 43(7):  1328-1338 .  doi:10.3864/j.issn.0578-1752.2010.07.002
    Abstract ( 1195 )   PDF (606KB) ( 803 )   Save
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    【Objective】 To explore the additive (A), epistatic (AA) and quantitative trait locus (QTL) ×environment interaction effects (QE) of QTL on dry matter accumulation of soybean seed for deepen understanding the nature of the yield formation and accelerating the breeding process. 【Method】 The aim of the present study was to measure A, AA and QE effects of QTL on dry matter accumulation in a population of 143 F5:9,F5:10 and F5:11 derived recombinant inbred lines developed from the cross between the soybean cultivars Charleston and Dongnong 594. 【Result】 Thirteen QTLs with A effect were detected at different developmental stages, eight of which had significant additive × environment (AE) effect. Fourteen AA pairwise QTLs were found, eight of which showed significant epistatise × environment (AAE) effect. Furthermore, only dmaC2_2, QTL with A effect could be found from 30 day to 80 day developmental stage, other QTLs with A effect and 14 AA pairwise QTLs were only found at some developmental stages. 【Conclusion】 The number of QTL with A effect and phenotypic variation explained by QTL with A effect, present “S” curve from 30 day to 80 day developmental stage, which was similar to phenotypic variation of dry matter accumulation of soybean seed. However, phenotypic variation explained by these AA pairwise QTLs was relatively stable and small. Additive effect, being high in 30 day developmental stage, decreased from 40 day to 70 day developmental stage, rising at 80 day developmental stage. Epistatic effects continuously rised from 30 day to 70 day developmental stage, slightly declined at 80 day developmental stage. QTL×environment effect had a greater impact on the dry matter accumulation of soybean seed from 30 day to 80 day developmental stage. QTL with additive effect, mostly located in linkage group C2 (the interval from OPK14_70 to satt134, corresponding to QTL including dmaC2_1, dmaC2_2 and dmaC2_3 ) at six developmental stages, especially at 30 day developmental stage. Loci of linkage group of QTL with additive effect had most change from 40 day to maturity, which had selectivity at developmental stage. QTL with epistasis effect, mostly located between linkage group C2 (the interval from OPK14_70 to satt134, corresponding to QTL dmaC2_1) and linkage group D1b (the interval from satt537 to sat_135, corresponding to QTL dmaD1b_1) at most developmental stages, except for 50 day developmental stage.

    Combining Ability and Genetic Effects of Germination Traits of Brassica napus L. Under Waterlogging Stress
    CHENG Yong,GU Min,CONG Ye,ZOU Chong-shun,ZHANG Xue-kun,WANG Han-zhong
    Scientia Agricultura Sinica. 2010, 43(7):  1339-1345 .  doi:10.3864/j.issn.0578-1752.2010.07.003
    Abstract ( 965 )   PDF (222KB) ( 659 )   Save
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    【Objective】 Cross combinations from six rapeseed cultivars and lines were investigated under waterlogging stress in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L. and to provide reasonable improvement programs. 【Method】 Six germination traits were investigated under waterlogging stress on the combining ability and heritability using complete diallel crossing method designed for 30 combinations from six cultivars and lines. The traits include relative root length, relative stem length, relative fresh weight per plant, relative survival rate, electrical conductivity and relative vigor index. After flooding treatment, the six traits of parents and F1 were measured and the general combining ability (GCA) and special combining ability (SCA) of germination traits were analyzed using GriffingⅠmethod. 【Result】 Among 30 cross combinations, the GCA was significantly different among the 6 waterlogging resistance traits. The SCA of these traits was significantly different except the SCA of electrical conductivity. As the representative trait of rapeseed tolerance to waterlogging, relative vigor index had the highest narrow heritability and relatively low broad heritability. Cultivar Zhongshuang 9 and P79 had high tolerance potential to waterlogging. 【Conclusion】 The combining ability and genetic effects analysis of relative vigor index during germination stage can be used to identify the waterlogging tolerance of rapeseed and improve the breeding program.

    Advances in Research of Festulolium Intergeneric Hybrids
    WEN Chang-long,ZHAO Bing,DU Jian-cai,YAMADA Toshihiko,GUO Yang-dong
    Scientia Agricultura Sinica. 2010, 43(7):  1346-1354 .  doi:10.3864/j.issn.0578-1752.2010.07.004
    Abstract ( 952 )   PDF (316KB) ( 690 )   Save
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    Intergeneric hybrids (Festulolium) between Lolium and Festuca species were being increasingly used worldwide as forage grasses, which combined yield performance of Lolium (L. multiflorum Lam. and L. perenne L.) and tolerance against abiotic stress of Festuca (F. pratensis Huds. and F. arundinacea Schreb.). Festulolium was being used to provide the grass breeders with more options to create novel germplasms. In addition, the complex of species was an unique material to investigate the genetic mechanism of forage plants. The yield, quality, resistance and chromosome characteristics of the hybrids were analyzed, and the improvement of the grasses using gene introgression, androgenesis and genetic modification methods was introduced. The latest advance in GISH, genetic map construction and QTL of Festulolium hybrids were described here.

    Role of Small GTP-Binding Protein ROP in M. truncatula in Symbiosis: 1. Isolation and Expression Analysis of MtROP5 Gene

    LIU Wei,CHEN Ai-min,FENG Li-xing,CAO Lian-pu,SUN Jie,WANG Yan-zhang

    Scientia Agricultura Sinica. 2010, 43(7):  1355-1362 .  doi:10.3864/j.issn.0578-1752.2010.07.005
    Abstract ( 944 )   PDF (665KB) ( 490 )   Save
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    【Objective】 The objective of this study is to isolate ROP (Rho GTPase of plant) gene from Medicago truncatula and analyze its expression pattern in order to further investigate the function of ROP in symbiotic interaction. 【Method】 Through analysis of comparative genomics, MtROP5 gene in M. truncatula was isolated by RT-PCR. Using semi-quantitative RT-PCR, the expression level of MtROP5 gene was detected in different tissues of M. truncatula, and real-time quantitative RT-PCR was used to detect the expression levels of MtROP5 gene in inoculated root which was infected by Sinorhizobium meliloti Rm1021 during the 72 hours post-inoculation. 【Result】 MtROP5 gene with a complete open reading frame of 826 bp encoding a peptide of 197 amino acid residues was isolated from M. truncatula. Results of sequence analysis showed that MtROP5 contains the typical structures of ROP GTPase family. Homologous comparison with some plant ROPs indicated that MtROP5 shared high similarity with other plant ROPs. Expression analysis of RT-PCR showed that MtROP5 gene expressed in root, stem, leaf, flower, nodule, especially higher expression in stem and flower, next in root and nodule, and the expression level of MtROP5 gene in leaf was lower. Compared with the expression level of MtROP5 gene in uninoculated root, the expression level of MtROP5 gene was up-regulated at the different stages (0 to 72 hours) post-inoculation. 【Conclusion】 A small GTPase MtROP5 gene in M. truncatula was obtained. MtROP5 gene may involve in the regulation of signal transmission that occur at early stage of symbiotic interaction between legume plant and Rhizobium.

    TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
    Maize Leaf Disease Spots Segmentation Based on Gauss-MRF Model
    LAI Jun-chen,TANG Xiu-juan,XIE Rui-zhi,BAI Zhong-ying,LI Shao-kun
    Scientia Agricultura Sinica. 2010, 43(7):  1363-1369 .  doi:10.3864/j.issn.0578-1752.2010.07.006
    Abstract ( 1123 )   PDF (483KB) ( 1175 )   Save
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    【Objective】 Image segmentation is one of the difficult issues in crop disease automatic identification systems, in present research, algorithms based on threshold or based on clustering were mostly used. These methods are simple and easy of implementation, but the precision is low. In order to improve the segmentation precision of maize disease spots, Gauss-MRF model was introduced to segment maize disease spot images. 【Method】 The algorithm was implemented on VC6.0. Gauss-Markov random field model takes advantage of both image intensity and spatial information imposed by Gibbs smoothness prior about the pixel labels and thus can be used to effectively segment the noised images. Four kinds of corn disease images were segmented, and segmentation results were compared with algorithms based on threshold and Gauss model. 【Result】 The segmentation algorithm based on G-MRF model showed higher precision, and the segmentation results showed accurate and closed boundaries. The mean correct classification ratio of G-MRF model was up to 96.35% which was higher than algorithms based on threshold and Gauss model, respectively, by 3.75% and 4.03%. 【Conclusion】 The research shows that the segmentation algorithm based on G-MRF model is satisfactory to separate disease part from normal part of leaves. The mean correct classification ratio is 96.35%. It is effective in segmenting and processing maize disease spots images.

    Effect of Exogenous Hormone on Plant Growth and Enzyme Activity of a Novel Cotton Dwarf-Mutant AS98
    ZHANG Chao,SUN Jun-ling,JIA Yin-hua,ZHOU Zhong-li,PAN Zhao-e,HE Shou-pu,XU Zheng-jun,DU Xiong-ming
    Scientia Agricultura Sinica. 2010, 43(7):  1370-1378 .  doi:10.3864/j.issn.0578-1752.2010.07.007
    Abstract ( 823 )   PDF (394KB) ( 599 )   Save
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    【Objective】 The purpose of this study was to illuminate the sensibility of the exogenous hormones to the plant height characters of a new dwarf mutant AS98 and determine which kind of hormone deficiency this mutant belongs to. 【Method】Two cotton lines, dwarf mutant AS98 and normal type LHF10W99, were used as materials in this research. AS98 was treated with different contents of exogenous GA3, IAA and BR. The changes of plant height, internode length and leaf number were investigated in different treatments. Meanwhile, the activities of α-amylase, POD and SOD of the mutant were analyzed after the mutant AS98 was treated with GA3 and PP333. 【Result】 The result indicated that the average plant height, internode length, boll weight and seed index of AS98 without hormone treatment were markedly lower than that of normal genotype LHF10W99, respectively, but their leaf number and lint percentage were not significantly different compared with that of LHF10W99. After being treated with 100 mg•L-1 exogenous GA3 continuously, the plant height and internode length of AS98 showed very significant difference compared with AS98 without being treated with hormone, and reached that of the normal type of LHF10W99. But the plant height and internode length of AS98 treated with IAA and BR did not show significant difference with that of the control. The regression analysis showed that there was a significant relationship between the exogenous GA3 and plant height, internode length of mutant AS98, but there was no significant relationship between the plant height and IAA and BR. Moreover, the exogenous GA3 could increase the α-amylase activity of AS98 and decrease POD and SOD activities. On the contrary, PP333 could reduce the α-amylase activity of AS98 and up-regulate POD and SOD activities. 【Conclusion】 It is concluded that AS98 is a new super-dwarf mutant with normal broadleaf. The plant height of AS98 is sensitive to the exogenous GA3, and can be resumed to normal height with exogenous GA3 continuous treatment. The α-amylase activity of AS98 is sensitive to exogenous GA3 and PP333. AS98 is a GA3-deficiency dwarf mutant.
    Effect of Foliar Spraying of H2O2 and Cu/Zn SOD and APX Gene Transfered in Chloroplasts on the Recoverability of Sweet Potato After Chilling Stress
    WU Xiao-bing,CHENG Yu-jie,DENG Xi-ping,KWAK Sang-soo
    Scientia Agricultura Sinica. 2010, 43(7):  1379-1388 .  doi:10.3864/j.issn.0578-1752.2010.07.008
    Abstract ( 1013 )   PDF (852KB) ( 586 )   Save
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    【Objective】 In an experiment, the recoverability of the sweetpotato, which expressed both Cu/Zn superoxide dismutase (SOD) and ascorbate peroxidase (APX) in chloroplasts, was compared with its control plants after a short time of chilling stress, and foliar application of exogenous hydrogen peroxide (H2O2) before chilling stress on enhancement of seedling recovery capability after chilling stress was studied.【Method】 The transgenic sweetpotato that simultaneously expressed both Cu/Zn SOD and APX in chloroplast and its non-transgenic control plants were used as materials, and the recoverability of them after one night (12 h) of chilling stress at 5℃, and the enhancement of chilling resistance when pretreated them with 1.0 mmol•L-1 H2O2 before chilling stress, the membrane permeability, anti-oxidative enzymes system and photosynthetic system of each plant were tested in this experiment. 【Result】 Soon after a short time (12 h) chilling stress, the activity of anti-oxidative enzymes of SOD, AXP and CAT (catalase) in non-transgenic sweet potato decreased significantly and so did the content of carotenoid, but the membrane permeability increased significantly, photosynthetic pigment and photosynthetic electron transport chain were damaged, so the photosynthetic rate reduced. After 26 h of recovery at room temperature (25℃), the activities of the above three mentioned anti-oxidative enzymes and the content of carotenoid all increased significantly, membrane permeability kept a tendency of increase, and photosynthetic electron transport chain was almost repaired completely while photosynthetic pigment decreased significantly, but the photosynthesis recovered to a large extent. Compared with non-transgenic sweetpotato after chilling stress, it was observed that in transgenic sweetpotato, the activities of the above three mentioned anti-oxidative enzymes and the content of caroternoid were higher, membrane permeability was lower, and furthermore the transgenic sweetpotato had a stronger ability to protect photosynthetic pigment and photosynthetic electron transport chain, therefore, the photosynthetic rate was relatively high. It was also observed that in the recovery process of the plants treated with 1.0 mmol•L-1 H2O2 before chilling stress, compared with the non-treatments, the recovery capabilities of the anti-oxidative enzymes were stronger, the content of MDA and membrane permeability were lower, and the growth status after chilling was better. 【Conclusion】 A stronger chilling-resistance ability was showed in transgenic sweetpotato compared with non-transgenic sweetpotato under the treatment of chilling stress, and so did a stronger recovery capability after stress. So the introduced genes of Cu/Zn SOD and APX provided sweetpotato an advantage against chilling. The pretreatment with 1.0 mmol•L-1 H2O2 improved the recovery capability of the sweetpotato plants after stress, and the chilling resistance was enhanced.

    PLANT PROTECTION
    Effects of the Biocontrol Agent Pseudomonas fluorescens 2P24 on Microbial Community Diversity in the Melon Rhizosphere
    ZHU Wei-jie,WANG Nan,YU Xue-ping,WANG Wei
    Scientia Agricultura Sinica. 2010, 43(7):  1389-1396 .  doi:10.3864/j.issn.0578-1752.2010.07.009
    Abstract ( 1085 )   PDF (448KB) ( 1346 )   Save
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    【Objective】 The objective of this study was to investigate the influence of biocontrol agent Pseudomonas fluorescens 2P24 on microecosystem in the rhizosphere of melon, and to provide biosafety evaluation for the application of the bioagent. 【Method】 The influence of biocontrol agent 2P24 on microecosystem in melon rhizosphere at different growing stages was investigated by using plate culture and terminal restriction fragment length polymorphism (T-RFLP) analysis. 【Result】 After transplantion, the rhizosphere biomass of bacteria and fungi in the strain 2P24-treated melon seedlings was decreased, while the population of actinomycetes was increased. In the harvest period, the influence of strain 2P24 on bacteria and actinomycetes was not significant, but the fungal population was promoted obviously. Totally 41 TRFs were obtained by T-RFLP analysis, among which the dominant floras of TRF213, TRF240 and TRF513 were not obviously affected, while the floras of TRF61, TRF348 and TRF365 were influenced significantly, which was also validated by the increased biodiversity indices (Shannon-Wiener). 【Conclusion】 The abundance bioinformation on the influence of strain 2P24 on microbial diversity was obtained by the methods combined with plate cultivation and T-RFLP analysis, and the results showed that the biocontrol agent 2P24 did not significantly affect the diversity and dynamics of microbial communities in melon rhizosphere.

    Rapid Molecular Detection Technologies of Citrus tristeza virus in Plant Tissues and Single Aphid
    LIU Yong-qing,CAO Meng-ji,WANG Xue-feng,LI Zhong-an,TANG Ke-zhi,ZHOU Chang-yong
    Scientia Agricultura Sinica. 2010, 43(7):  1397-1403 .  doi:10.3864/j.issn.0578-1752.2010.07.010
    Abstract ( 986 )   PDF (744KB) ( 705 )   Save
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    【Objective】 The objective of this study was to explore a kind of quick, simple, sensitive and reliable method to detect Citrus tristeza virus in plant tissue and single aphid. 【Method】 RT-PCR, RT-nested-PCR and PC-RT-nested-PCR methods were used to detect CTV in pummelo inoculated CTV for at least 4 years and the positive rate and sensitivity of samples detected by these 3 methods were compared and the validity in detection of CTV in aphids was made by SC-RT-nested-PCR. 【Result】 Templates were used and total nucleic acid or virus RNA obtained from imprinting after various dilutions were detected by the methods of RT-PCR, RT-nested-PCR and PC-RT-nested-PCR, and the thresholds of detection were found to be 10-3, 10-5 and 10-1 folds, respectively. The sensitivity of detection of CTV by nested-PCR was up to 13-14 copies•μL-1. Fresh viviparity (parthenogenetic) brown citrus aphids were fed on CTV infected and virus-free plants of Guanxi pummelo for a week and squashed onto Whaterman filter paper and then detected by SC-RT-nested-PCR. The 132 bp expected target PCR products were obtained in all the brown citrus aphids fed on the infected plants of Guanxi pummelo besides those fed on the virus-free plants of Guanxi pummelo. 【Conclusion】 The methods of PC-RT-nested-PCR and RT-nested-PCR showed the same positive rate of detected samples. It is efficient to detect CTV in single aphid using SC-RT-nested-PCR and there is no need to extract nucleic acid employing PC-RT-nested-PCR and SC-RT-nested-PCR methods, which are applicable to certification of virus-free citrus plants or scion as well as to the studies on monitoring and epidemiology of CTV.

    SOIL & FERTILIZER·WATER-SAVING IRRIGATION·AGROECOLOGY & ENVIRONMENT
    Effects of Long-term Application of Chemical Fertilizer, Pig Manure and Rice Straw on Physical Properties of a Reddish Paddy Soil
    NIE Jun,ZHENG Sheng-xian,YANG Zeng-ping,LIAO Yu-lin,XIE Jian
    Scientia Agricultura Sinica. 2010, 43(7):  1404-1413 .  doi:10.3864/j.issn.0578-1752.2010.07.011
    Abstract ( 1050 )   PDF (468KB) ( 776 )   Save
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    【Objective】 The effect of long-term combined application of chemical fertilizer with pig manure (PM) and rice straw (RS) on physical properties were investigated in a reddish paddy soil of double rice cropping system in southern China.【Method】 The physical properties in seven treatments composed of N, P and K fertilizer and combined application of chemical fertilizer with RS from a long-term experimental field established in 1981 were evaluated to study the effects of fertilization on soil properties of a reddish paddy soil (classified as typical stagnic Anthrosol) derived from parent materials of Quaternary red clay. 【Result】 Results showed that long-term combined application of pig manure (PM), rice straw (RS) with chemical fertilizer decreased significantly the soil bulk density and the soil particle density, and increased the porosity, and the improved effect of PM was similar to that of RS. Combined application of PM and RS with chemical fertilizer were in favor of forming 5-0.5 mm water stable aggregate (WSA) and increased soil aggregate stability compared with application of chemical fertilizer alone. Soil water holding capacity (WHC) in plow layer was higher in combined application of PM and RS treatments than in chemical fertilizer treatments. 【Conclusion】 Long-term combined application of PM and RS with chemical fertilizer decreased significantly the soil bulk density and soil particle density, increased porosity, soil aggregate stability and soil water holding capacity, which was an effective measure to improve soil physical quality and soil fertility in reddish paddy soil.

    Effect of N, P, K Application on Yield, Nutrient and Water Utilization Under Sudangrass and Ryegrass Rotation Regime
    LI Wen-xi,LU Jian-wei,CHEN Fang,LI Xiao-kun
    Scientia Agricultura Sinica. 2010, 43(7):  1414-1422 .  doi:10.3864/j.issn.0578-1752.2010.07.012
    Abstract ( 910 )   PDF (294KB) ( 438 )   Save
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    【Objective】 Sudangrass and ryegrass rotation is a new type of cropping system in Jianghan Plain, which developed very fast in recent years. So it is essential to understand the optimum nutrient and water management measures in this new system.【Method】 Effect of NPK fertilizer on yield of forage grass, nutrition and water utilization under sudangrass and ryegrass rotation was studied through continuous pot experiments for three years. 【Result】 The results showed that NPK combination could obviously improve the yield of forage grass, and the total yield in the period of 2005-2006, 2006-2007, 2007-2008 was 1 690.0 g/pot, 2 091.3 g/pot, 1 770.7 g/pot, and yield in PK treatment (No N) was 700.7%, 1 256.9%, 856.3% lower than that of NPK treatment, and yield in NK treatment (No P) was 426.3%, 384.9%, 792.3% lower than that of NPK treatment, and yield for NP treatment were 15.9%, 4.4%, 10.6% lower than that of NPK treatment, respectively. NPK combination could improve nutrition uptake, and total N uptake in the period of 2005-2006, 2006-2007, 2007-2008 were 6.36 g/pot, 4.91 g/pot, 6.85 g/pot, and was 10.0 times, 14.8 times, 10.6 times higher than that of PK treatment, and was 3.7 times, 1.8 times, 5.1 times higher than that of NK treatment, respectively, but was similar to NP treatment. Total P uptake were 0.79 g/pot, 1.01 g/pot, 0.82 g/pot, and was 4.6 times, 6.8 times, 5.3 times higher than that of PK treatment, and was 2.4 times, 2.3 times, 2.9 times higher than that of NK treatment, respectively, but was similar to NP treatment. Total K uptake were 11.58 g/pot, 6.36 g/pot, 5.62 g/pot, and was 5.2 times, 8.4 times, 4.9 times higher than that of PK treatment, and 3.9 times, 2.3 times, 3.9 times higher than that of NK treatment, and were 80.9%, 57.4%, 200.5% higher than that of NP treatment, respectively. Water productivity in three years was 16.5 kg•m-3, 16.1 kg•m-3, 16.2 kg•m-3, and was 3.8 times, 5.4 times, 4.2 times higher than that of PK treatment, and was 2.3 times, 1.3 times, 2.6 times higher than that of NK treatment, and was 16.4%, 8.8%, 22.4% higher than that of NP treatment, respectively. In this rotation, soil pH degraded, but soil organic matter all upgraded. Soil total N in NP, NK, NPK treatments upgraded, but soil total N in PK was steady. Soil extractable P in NP, PK and NPK treatments upgraded obviously, and soil extractable P in NK increased slightly. Soil available K in NK and PK treatments upgraded obviously, but available K in NP and NPK degraded. 【Conclusion】 NPK combination increased yield of forage, improved nutrient uptake and soil fertility in sudangrass and ryegrass rotation system.
    HORTICULTURE
    Study on the Characteristics of Absorption, Distribution and Selective Transport of Na+ and K+ in Tomato Plants Under Salt Stress
    WANG Xue-zheng,LI Qiu-hong,WU Feng-zhi
    Scientia Agricultura Sinica. 2010, 43(7):  1423-1432 .  doi:10.3864/j.issn.0578-1752.2010.07.013
    Abstract ( 893 )   PDF (464KB) ( 773 )   Save
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    【Objective】 This experiment was carried out to elucidate the effects of salt stress on absorption, distribution and selective transport of Na+ and K+ in tomato plants. 【Method】 The absorption, distribution and selective transport of Na+ and K+in tomato plants under salt stress were analyzed by atomic absorption spectrometry. 【Result】 The results showed that with salt stress concentration and time increased, Na+ absorption of tomatoes increased, the fundamental order of accumulation in various organs was root>stem>leaf. The total accumulation of Na+ in salt-tolerant cultivar was lower than that in salt-sensitive one. Under salt stress, Na+ contents in tomato leaves, stems and roots were increased with the increase of NaCl concentration. Na+ contents in salt-tolerant cultivar were lower than that in salt-sensitive one. From the regional distribution of ions in the tomato plant, there was a higher Na+ proportion in rhizomes of salt-tolerant cultivar; the distribution of potassium was more focused in leaves. The salt-sensitive cultivar tended to allocate Na+ to the leaves. Under early salt stress, the salt concentration was 200 mmol•L-1 and more. The choice of K+ transport in tomato plants to shoot with the stress showed a downward trend. Below 200 mmol•L-1 showed a good alternative transportation, Sk/Na (transport) of salt-tolerant cultivar were higher than that of salt-sensitive cultivar. Root of salt-tolerant cultivar showed a greater K+ transport ability. 【Conclusion】 The lower Na+ content in leaves and better alternative transportation of K+ under salt stress are the most important characteristics of salt tolerant tomato varieties.

    A Study on Coloration Physiology of Fruit in Two Red Chinese Sand Pear Cultivars ‘Meirensu’ and ‘Yunhongli No.1’
    HUANG Chun-hui,YU Bo,SU Jun,SHU Qun,TENG Yuan-wen
    Scientia Agricultura Sinica. 2010, 43(7):  1433-1440 .  doi:10.3864/j.issn.0578-1752.2010.07.014
    Abstract ( 970 )   PDF (496KB) ( 881 )   Save
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    【Objective】 In order to understand the mechanism of coloring of red Chinese sand pears, the relationships between pigments biosynthesis and related enzymes activities as well as the contents of soluble sugars were studied in genetically different red Chinese sand pear cultivars. 【Method】 Two red Chinese sand pear cultivars ‘Meirensu’ and ‘Yunhongli No.1’ were used to investigate the changes in the concentrations of anthocyanin, chlorophyll, carotenoid, flavonoid, total phenolics, and the activities of PAL and UFGT in fruit peel as well as the contents of soluble sugars in fruit flesh during the period of fruit development. The total anthocyanin was estimated by a pH differential method. The concentrations of chlorophyll, carotenoid, flavonoid and total phenolics were determined by colorimetric assay. The activity of PAL was measured by a colorimetric assay, but the activity of UFGT was assayed by HPLC. The concentration and composition of soluble sugars were detected using HPLC. 【Result】 Although the trends of physiological changes were similar in two cultivars, the concentration of anthocyanin in ‘Yunhongli No.1’ was higher than in ‘Meirensu’ at the maturation stage of fruit. At the early stage of fruit development, the concentrations of chlorophyll, carotenoid, flavonoid and total phenolics all increased, but the concentration of anthocyanin was too small to detect. From the beginning of 13 weeks after anthesis, anthocyanin accumulated rapidly with degrading chlorophyll and reached the highest content when fruit harvested. The activities of PAL and UFGT were high when anthocyanin began to biosynthesize in fruit peel. With the accumulation of anthocyanin, the activity of PAL decreased, but the activity of UFGT remained at a high level later. During the fruit development, the content of total soluble sugars increased gradually and the accumulation of sucrose was in parallel with the increase of anthocyanin. 【Conclusion】 Fruit coloration in red Chinese sand pear is accompanied by fruit maturation. Chlorophyll degradation and anthocyanin accumulation made the fruit skin red. Anthocyanin biosynthesis might be induced by PAL, while anthocyanin accumulation is closely related to UFGT activity. Anthocyanin biosynthesis is determined primarily by genotypes and the potential of anthocyanin synthesis is higher in Yunhongli No. 1 than in Meirensu. The accumulation of anthocyanin is in parallel with the changes of total soluble sugar.

    Effects of Salicylic Acid on Plasma Membrane ATPase and Free Radical of Grape Root Under Cadmium Stress
    SHAO Xiao-jie,YANG Hong-qiang,RAN Kun,JIANG Qian-qian,SUN Xiao-li
    Scientia Agricultura Sinica. 2010, 43(7):  1441-1447 .  doi:10.3864/j.issn.0578-1752.2010.07.015
    Abstract ( 970 )   PDF (248KB) ( 737 )   Save
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    【Objective】 To explore the effect of salicylic acid (SA) on cadmium stress and the pathway of alleviating cadmium damage to grapes roots. 【Method】 The experiment was carried out with the cutting seedlings of Zexiang grape pretreated by salicylic acid under CdCl2 stress via hydroponics. The activity of root, the activity of H+-ATPase and Ca2+-ATPase in plasma membrane (PM), and the formation of reactive oxygen species and nitric oxide (NO) were determine. 【Result】 The 0.01 mmol•L-1 CdCl2 increased the activity of root and PM Ca2+-ATPase. 1.0 mmol•L-1 CdCl2 promoted the formation of , H2O2 and NO, and inhibited significantly root activity and the activity of H+-ATPase and Ca2+-ATPase in PM. Pretreatment of SA at 50 μmol•L-1 greatly decreased the formation of , H2O2 and NO, which retarded the declining of root activity and the activity of H+-ATPase and Ca2+-ATPase in PM under 1.0 mmol•L-1 CdCl2 treatment. This effect of SA on roots decreased when SA concentration was raised to 200 μmol•L-1. 【Conclusion】It was found that SA at 50 μmol•L-1 is the optimal concentration for Alleviation of the damage of cadmium on grape roots, and at this concentration, SA mitigated the injurious effects of cadmium on root activity and PM ATPase in roots of grape by inhibiting the formation of free radicals.

    Molecular Cloning of Sugarcane S-Adenosylmethionine Decarboxylase Gene (Sc-SAMDC) and Its Expression Analysis
    LIU Jin-xian,QUE You-xiong,GUO Jin-long,XU Li-ping,XU Jing-sheng,CHEN Ru-kai
    Scientia Agricultura Sinica. 2010, 43(7):  1448-1457 .  doi:10.3864/j.issn.0578-1752.2010.07.016
    Abstract ( 1038 )   PDF (1162KB) ( 827 )   Save
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    【Objective】 In this study, the obtainment and sequence analysis of the S-adenosylmethionine decarboxylase (SAMDC) gene from sugarcane (Saccharum officinarum) was conducted, and then its expression in prokaryotic system and its expression profiles under different stress treatments were also carried out. 【Method】 Firstly, through extensive sequencing and bioinformatics analysis, the full-length cDNA of sugarcane SAMDC gene, named as Sc-SAMDC, was obtained from sugarcane stem cDNA library, and its sequence characters were also analyzed. Secondly, the fused expression plasmid was constructed by inserting the cDNA fragment encoding the mature peptide of SAMDC into prokaryotic expression vector pET29a(+), and the positive recombinant was transformed into Esherichia coli BL21(DE3). Finally, the expression profiles of Sc-SAMDC in sugarcane seedling under different stresses were analyzed by Real-time qPCR. 【Result】 Sequence analysis showed that the full-length cDNA sequence of Sc-SAMDC (GenBank Accession number: GQ246459) was 1 968 bp, with three open reading frames (ORFs), tiny ORF (tORF), upstream ORF (uORF) and main ORF(mORF). The mORF was 1 200 bp encoding 399 amino acid residues with a molecular mass of 43.6 kD, and the deduced protein had two highly conserved function domains (proenzyme cleavage site and PEST domain). The SDS-PAGE showed that the expression protein is a fusion protein and the molecular weight is about 50 kD. The result of Real time qPCR analysis showed that Sc-SAMDC responded differently to various exogenous treatments, induced by both PEG and NaCl, but inhibited by SA and H2O2. 【Conclusion】 A SAMDC gene from sugarcane was successfully cloned and expressed in E. coli, the sequence characters and the expression profiles of this gene under different stresses were also analyzed.

    STORAGE·FRESH-KEEPING·PROCESSING
    Variability of Pesticide Residues in Vegetables from the Marketplaces in Ji’nan City
    SONG Yu-feng,LÜ,Xiao,REN Feng-shan
    Scientia Agricultura Sinica. 2010, 43(7):  1458-1463 .  doi:10.3864/j.issn.0578-1752.2010.07.017
    Abstract ( 1151 )   PDF (386KB) ( 784 )   Save
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    【Objective】 In order to provide technological support for risk estimation of pesticide residues taken from vegetables, the pollution of pesticide in vegetables in Ji’nan city was investigated. Moreover, the variability of pesticide residues in vegetables was explored, and the variability factor was calculated. 【Method】 The level of pesticide pollution was studied by statistic method. The variability factor was calculated using the Harrell-Davis method in accordance with principles recommended by the JMPR. In addition, the procedure of evaluation was validated according to the principles laid down by the JMPR. 【Result】 The detection rate of pesticide residues in all marketplace samples was less than 20% in Ji’nan city. The unqualified rate of vegetables was low (0.6%). The pesticide with highest rate of detection was chlorothalonil. The vegetables with highest rate of pesticide residues detection were leafy vegetables. The relationship between variability factor and mean value of concentrations of contaminations could be expressed by the formula, . 【Conclusion】 The pollution of pesticide residues in vegetables in Ji’nan city is light. The evaluated variability factor is larger than that the value recommended by the JMPR, however, less than the default value used for acute intake assessment of pesticide residues in UK in most cases.

    Cloning of the CBHI Gene of Goose-Origin Penicillium oxalicum Currie & Thom and Its Eukaryotic Expression Vector Construction
    WANG Bao-wei,ZHANG Qian,GE Wen-hua,ZHANG Ming-ai,YUE Bin,HUANG Guo-qing
    Scientia Agricultura Sinica. 2010, 43(7):  1464-1472 .  doi:10.3864/j.issn.0578-1752.2010.07.018
    Abstract ( 870 )   PDF (632KB) ( 695 )   Save
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    【Objective】 The aim of the study was to clone the cellobiohydrolase gene (CBHⅠ) of goose-origin Penicillium oxalicum Currie & Thom F67 and construct the eukaryotic expression vector for the gene. 【Method】 A fragment of the CBHⅠ gene was amplified by degenerate PCR, the 5′and 3′ flanking sequences of CBHⅠ gene were cloned using TAIL-PCR, and the full-length sequence of the CBHⅠ gene was cloned by RT-PCR. The construction of the eukaryotic expression vector for the gene was also studied. 【Result】 Fragment A (EU574736), 5′ sequence B1 (EU603295), 3′ sequence B2 (EU652768) and full-length sequence C (EU727171) of the CBHⅠ gene were cloned successfully and an eukaryotic expression vector named pPIC9K-CBHⅠ was constructed for the gene. The bioinformatics analysis showed that the gene had the highest homology with the gene of Penicillium janthinellum, which reached up to 76%. The first 26 amino acids might be a signal peptide sequence with the hydrophobicity of up to 2.63. The CBHⅠ gene consisted of the catalytic domain, convergence zone and cellulose-binding domain and its tertiary structure was mainly composed of β-sheets. 【Conclusion】 The successful cloning of the full-length sequence of CBHⅠ gene of goose-origin Penicillium oxalicum Currie & Thom F67 enriched the biological information resource of filamentous fungi, and the construction of the eukaryotic expression vector pPIC9K-CBHⅠ has laid a foundation for the expression of the CBHⅠ gene in eukaryotic hosts and the availability of high-performance engineering strains.

    ANIMAL SCIENCE·RESOURCE INSECT
    HPT Axis HSP70 mRNA Dynamic Expression During Cold Stress of Goose
    TU Yun-jie,CHEN Guo-hong,GENG Zhao-yu,SU Yi-jun,WANG Ke-hua
    Scientia Agricultura Sinica. 2010, 43(7):  1473-1479 .  doi:10.3864/j.issn.0578-1752.2010.07.019
    Abstract ( 848 )   PDF (433KB) ( 732 )   Save
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    【Objective】 The objective of this study was to analyze the expression of HSP70 mRNA in Hypothalamic-Pituitary- Thyroid (HPT) axis under cold stress (12±1℃). 【Method】 The dynamic expression of HSP70 mRNA in HPT axis of 7 d Wanxi White goose was got utilizing real-time fluorescent quantification reverse transcriptase PCR (FQ-RT-PCR). 【Result】 Hypothalamic HSP70 mRNA transcription level went up significantly at1.5, 6, and 9 h of cold stress; It decreased to normal level in the other times. It increased again after cold exposure for 6 hours, moreover, it went up to the highest level at 6 h. Hereafter it declined to normal level. Pituitary HSP70 mRNA transcription level descended significantly at 0.5, 1.5, 6, and 12 h . It went up again gradually to normal level in the next 12 hours. It decreased again significantly at 0.5, 3, 6 h after cold exposure, hereafter gradually increased to normal level. Thyroid HSP70 mRNA transcription level went up quickly at 0.5h, hereafter decreased at 3, 6, 12 h significantly under cold stress. It went up significantly at 0.5h and 3h and it was down-regulated gradually to normal level in the other times after cold stress. 【Conclusion】 The expression rule of HSP70 mRNA was different in Hypothalamic-Pituitary-Thyroid (HPT) axis. Hypothalamic HSP70 mRNA transcription level was the highest which showed going up trend as a whole. HSP70 was the up-regulation gene of hypothalamic in cold stress reaction. Pituitary and thyroid HSP70 mRNA transcription level was repressed which showed that it was the down-regulation gene of pituitary and thyroid in cold stress reaction.

    VETERINARY SCIENCE
    Identification of Antigen Epitope Located at the N Terminal Nuclear Localization Signal Region in Capsid Protein of Porcine Circovirus Type 2 (PCV2)
    GUO Long-jun,LU Yue-hua,HUANG Li-ping,WEI Yan-wu,LIU Chang-ming
    Scientia Agricultura Sinica. 2010, 43(7):  1480-1486 .  doi:10.3864/j.issn.0578-1752.2010.07.020
    Abstract ( 847 )   PDF (543KB) ( 1341 )   Save
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    【Objective】 Porcine circovirus type 2 (PCV2) is an important causative agent of postweaning multisystemic syndrome in pigs and capsid protein (Cap) encoded by ORF2 as the main structural protein is involved in the host immune protective response, so it is very important to identify the antigenic epitopes of PCV2 Cap. 【Method】 In this study, five monoclonal antibodies (MAbs) against recombinant PCV2-ORF2 Cap expressed by baculovirus system were generated and preliminary epitopes region was localized using the five MAbs after expression of truncated fragments from ORF2 gene in Echerichia coli system. Subsequently, peptides were synthesized to further accurately identify epitopes on the Cap. 【Result】 Of the five MAbs, four MAbs were against the same core epitope (26RPWLVHPRHRY36) verified by peptides mapping, locating in nuclear localization signal region at the N terminal of Cap. Besides, another MAb (1D2) could not react with the four truncated fragments only to react with the whole recombinant Cap, and it may be a conformational epitope based on its neutralizing effect against PCV2. 【Conclusion】 It was concluded that an epitope located in nuclear localization signal region of Cap was firstly reported, which will provide a basis for further studies on the functions of Cap as well as on the mechanism of Cap localization into nuclear.

    Study on the Accumulation of Fluoroquinolones in QnrS-Positive Animal Clinical Isolates of Escherichia coli
    YANG Yan-lin,YUE Lei,LI Shu-juan,XUE Guo-cong,LI Lu-lu,CHEN Chao-xi,ZHANG Wen-jian,WU Huan-peng,LIU Ya-hong
    Scientia Agricultura Sinica. 2010, 43(7):  1487-1492 .  doi:10.3864/j.issn.0578-1752.2010.07.021
    Abstract ( 811 )   PDF (361KB) ( 469 )   Save
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    【Objective】 The objective of the experiment was to determine the susceptibility of fluoroquinolones and the effect of active efflux pump in QnrS-positive animal clinical isolates of E. coli. 【Method】 The broth dilution method was used to determine MICs of fluoroquinolones against the QnrS-positive isolates. The accumulation of ciprofloxacin and the effect of efflux pump inhibitor,carbonyl cyanide m-chlorophenyl hydrazone (CCCP) for tested isolates of E. coli were measured by a fluorescenece method.【Result】 The susceptibility of QnrS-positive animal clinical isolates of E. coli to fluoroquinolone antibiotics varied greatly and decreased with energy dependence. The decrease in resistant isolates with QnrS was prominent. CCCP could increase the accumulation of ciprofloxacin in both the susceptible and the resistant strains of QnrS-positive isolates.However,the decrease of the latter was lower than the former. 【Conclusion】 The accumulation of ciprofloxacin in QnrS-positive animal clinical isolates of E. coli could be reduced and lower than the effective concentration by activating of active efflux pump,which affected the plasmid-mediated resistance.

    The in vitro Antibacterial Activities and Post-Antibiotic Effects of the Ceftiofur Suspension
    WANG Hui,LIU Wei,CHEN Xiao-jun,LIU Zhi-kui,SUN Zhi-liang
    Scientia Agricultura Sinica. 2010, 43(7):  1493-1499 .  doi:10.3864/j.issn.0578-1752.2010.07.022
    Abstract ( 903 )   PDF (349KB) ( 815 )   Save
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    【Objective】 The objective of the study was to evaluate the in vitro antibacterial activity and post-antibiotic effect of ceftiofur suspension on three standard bacteria strains in veterinary clinic. 【Method】 Minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested by double dilution method to three standard bacteria strains. Time-kill curve was drew according to colony count. Post-antibiotic effect (PAE) was determined by plate count. 【Result】 MIC value of ceftiofur suspension to E. coli, Actinobacillus and Streptococcus zooepidemicus was 0.076, 0.304, and 0.00475 μg•mL-1 respectively. MBC value was 0.61, 0.304, and 0.00475 μg•mL-1 respectively. Sterilization rate of ceftiofur suspension was the fastest to Actinobacillus, followed by Streptococcus. PAE of ceftiofur suspension was relatively short to E.coli, which illustrated that it was nonconcentration dependent. PAE was obvious longer to Actinobacillus, which showed that it was concentration dependent, however, it revealed part concentration dependent to streptococcus. 【Conclusion】Ceftiofur suspension can be widely used in veterinariy clinic due to its strong, immediate, and persistent sterilization.

    RESEARCH NOTES
    Sensitivity of Potato Cultivars (Solanum tuberosum L.) to Temperature and Photoperiod and the Relationship with Some Endogenous Hormone
    XIAO Guan-li,GUO Hua-chun
    Scientia Agricultura Sinica. 2010, 43(7):  1500-1507 .  doi:10.3864/j.issn.0578-1752.2010.07.023
    Abstract ( 817 )   PDF (281KB) ( 643 )   Save
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    【Objective】 The relationship between potato growth, tuber formation and endogenous GA3,ABA and JA was studied with an aim to provide a basis for the balanced production and variety introduction of potato in Yunnan. 【Method】 Four main potato cultivars used in Yunnan, including Atlantic, Cooperation 88, Mira and Zhongdianhong, were planted under 6 different temperature and photoperiod treatments (15℃8 h, 15℃12 h , 15℃16 h , 25℃8 h, 25℃12 h and 25℃16 h). 【Result】 Results showed that the sensitivity of potato cultivars to temperature and photoperiod was significantly different. Variety of Atlantic was sensitive to temperature and no tuber formed in treatments of 25℃8 h, 25℃12 h and 25℃16 h, variety of Cooperation 88 was sensitive to photoperiod and no tuber formed in temperature-photoperiod treatments of 15℃16 h and 25℃16 h, no tuber formed for the variety of Zhongdianhong in treatment of 25℃16 h. Only Mira formed tuber in all treatments. Contents of endogenous GA3, ABA and JA in potato leaves were evaluated, and the results showed that the content of GA3 was high in no tuber form conditions and was low in tuber formation condition, content of ABA and JA increased with the potato development in any conditions. 【Conclusion】 GA3 was an important factor inhibiting the tuber formation of potato, content of ABA and JA was more significantly related with senescence than the tuber formation.

    Construction of a Molecular Genetic Linkage Map and QTL Analysis of the First Pistillate Flower Node Trait in Chieh-qua
    CHENG Zhi-xue,CHEN Qing-hua,PENG Qing-wu,ZHANG Hua,WANG Rui
    Scientia Agricultura Sinica. 2010, 43(7):  1508-1515 .  doi:10.3864/j.issn.0578-1752.2010.07.024
    Abstract ( 837 )   PDF (565KB) ( 738 )   Save
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    【Objective】 The aims of this paper are to construct a molecular genetic linkage map and locate the first pistillate flower node traits of chieh-qua, which will provide a scientific basis for establishing molecular marker of breeding, female gene cloning and gene transfer. 【Method】 In this study, a population of F2 generation including 115 individual plants was derived from the cross between the homozygous weak female lines G4 and the homozygous gynoecious line K36, the AFLP, RAPD and SRAP markers were used in constructing a molecular genetic map and mapping QTL traits controlling the first pistillate flower bearing node. 【Result】 This molecular genetic linkage map included 13 linkage groups and contained 93 AFLP markers, 16 RAPD markers, 35 SRAP markers respectively. This map was 1 651.9 cM, and the average distance between two markers was 11.47 cM. Mapping of the quantitative trait loci of the first pistillate flower node was analyzed by software QTL Network 2.0, and 3 QTLs were found on the map, named as fn1, fn2, fn3. fnl located on linkage group1, fn2 and fn3 located on linkage group6. They accounted for 62.54%, 0.2%, 37.39% of the phenotypic variance, respectively. 【Conclusion】 A genetic linkage map was firstly constructed,and three QTLs was located which control first pistillate flower node traits of chieh-qua, thus providing a scientific basis for further cloning of the female-related gene and molecular marker-assisted selection breeding.

    Establishment and Application of S-SAP System in Malus domestica
    ZHAO Gui-ling,ZHANG Zhi-hong,MA Yue,CHANG Lin-lin,WANG Kun,DAI Hong-yan
    Scientia Agricultura Sinica. 2010, 43(7):  1516-1523 .  doi:10.3864/j.issn.0578-1752.2010.07.025
    Abstract ( 1027 )   PDF (695KB) ( 666 )   Save
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    【Objective】 This study aimed at establishing and optimizing S-SAP system of apple, exploring the possibility of using S-SAP system to distinguish apple bud sports, lay a foundation for distinguishing and utilizing of apple bud sports at DNA molecular level. 【Method】 The primary S-SAP system was established using Fuji, Hanfu and Gala. Thirty-two primer combinations were screened according to band number variability and polymorphism. The effects of DNA restriction enzyme digestion, PCR amplification and silver stained method on S-SAP analysis of apple were studied. Eight Delicious bud sports were analyzed by S-SAP with six primer combinations. The SIMQUAL program of NTsys-pc2 software was adopted to calculate similarity coefficient. The cluster analysis was performed using UPGAM method, and the dendrogram was generated by Treeplot program. 【Result】 The optimum S-SAP for apple was as follows: Total DNA extracted with modified CTAB method. The total genome DNA was cut using MseⅠ/PstⅠdouble digests. The Taq DNA polymerase from Fermentas was used to perform PCR amplification. The selective PCR products were separated by 6% denatured polyacrylamide gel and the different fragments were detected by modified mild alkali method. Six S-SAP primer combinations that are suitable for apple cultivar were screened, and the LTRP1/Mtcc primer combination presented polymorphic bands in Red Spur Delicious, Starking Delicious and Xinyuanshuai. The similarity coefficient of the analyzed materials ranged from 0.88 to 0.98. Eight Delicious bud sports could be grouped into four distinct families based on similarity of 0.93. 【Conclusion】 Ty1-copia-based S-SAP system was established and six S-SAP primer combinations that are suitable for apple cultivar were screened, and the Delicious bud sports could be differentiated by LTRP1/Mtcc primer combination.

    Isolation of Microbial Strains Producing Acidic Xylanase and Characterization of the Enzyme
    GUO Chun-yan,DIAO Qi-yu,QIAO Yu,TU Yan,ZHANG Nai-feng,JIANG Cheng-gang
    Scientia Agricultura Sinica. 2010, 43(7):  1524-1530 .  doi:10.3864/j.issn.0578-1752.2010.07.026
    Abstract ( 794 )   PDF (325KB) ( 682 )   Save
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    【Objective】 This study was aiming at screening acidic xylanase-producing microbes from natural environment for potential use in feed industry. 【Method】 Eighteen xylanase-producing strains were isolated from soil by enrichment culture techniques. Five strains were chosen to ferment in shaking flasks. Strain S8-3, which showed the highest xylanase production, was preliminarily identified by standard methods, and the property of the xylanase produced by the strain was studied. 【Result】 Strain S8-3 was identified as Aspergillus niger. The maximal enzymatic activity of xylanase in culture solution was 628.43 U•mL-1. The xylanase activity preformed optimally at 45℃ and pH 4.5. The xylanase was stable at pH ranging from 3.0 to 7.0 and retained more than 60 % of its original activity after incubation for 30 min at 70℃. 【Conclusion】 The xylanase produced by strain S8-3 in this study may have the potential in feed industry.

    Cloning, Expression and Biological Function Analysis of the Novel Gene Sj Cyclophilin A of Schistosoma Japonicum
    PENG Jin-biao,HAN Hong-xiao,HONG Yang,WANG Xin-zhi,SHI Yao-jun,FU Zhi-qiang,LIU Jin-ming,LIN Jiao-jiao
    Scientia Agricultura Sinica. 2010, 43(7):  1531-1538 .  doi:10.3864/j.issn.0578-1752.2010.07.027
    Abstract ( 828 )   PDF (449KB) ( 653 )   Save
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    【Objective】 The present study was intended to clone a cDNA encoding cyclophilin A in Schistosoma japonicum and subsequently investigate its molecular functions as well as immunoprotective potential as a vaccine candidate for schistosomasis . 【Method】 Polymerase chain reaction (PCR) technique was employed to amplify the full-length cDNA encoding cyclophilin A of schistosomula (Sj CyPA) by employing a schistosomula specific enrichment cDNA library as the template. The expression profiles of Sj CyPA were determined at several different development stages by using real-time RT-PCR. The cDNA containing the open reading frame (ORF) of CyPA was subcloned into a pET28a(+) vector and the recombinant plasmid was transformed into competent E.coil/BL21 for producing recombinant protein. The PPIase activity of recombinant protein was determined by chymotrypsin-coupled chromogenic assay, and its antigenicity was confirmed by Western blot. The immunoprotective potential immunized by recombinant Sj CyPA in mice was also evaluated in the present study. 【Result】 The length of cDNA containing Sj CyPA ORF is 519 base pairs, encoding 172 amino acids. As determined by real-time PCR, the highest expression of Sj CyPA was observed at the transcript level at 13-day schistosomula stage, indicating that Sj CyPA was a abundant expression gene at schistosomula stage. The expressions of Sj CyPA both at transprict level and at protein level were not significantly alternated upon the treatment by cyclosporin A as determined by real time PCR and Western blot. Expectly, chymotrypsin- coupled chromogenic assay confirmed that Sj CyPA had PPIase activity and Western blot indicated that Sj CyPA was able to induce specific antibodies. Additionally, animal experiment showed that 18.72% worm reduction and 44.6% egg reduction were achieved in mice vaccinated with recombinant CyPA protein, respectively. 【Conclusion】 A full-length cDNA encoding Sj CyPA was obtained and its molecular characterizations were preliminarily investigated. Moreover, it was observed that the vaccination of recombinant protein of Sj CyPA could induce certain potential against schistosome schistosomasis.