Scientia Agricultura Sinica

Identification and Gene Mapping of a Novel Short Root Hair Mutant in Rice

DING Wo-Na, TONG Yan-Li, WU Jing, ZHU Shi-Hua

Scientia Agricultura Sinica. 2011, 44(21): 4333-4339. doi:10.3864/j.issn.0578-1752.2011.21.001

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【Objective】The identification and cloning of novel root hair-related genes in rice would play an important role in understanding the molecular genetic mechanisms of root hair development.【Method】A rice (Oryza sativa L.) mutant was isolated from a T-DNA insertion mutant library. Solution culture, phenotypic study, statistics analysis of segregation of different phenotypes as well as gene mapping by map-based cloning were used to study the phenotypic and genetic characteristics of the Ossrh1 mutant and map the OsSRH1 gene. 【Result】 The root hairs of young mutant seedlings were shorter and only 36% of the wild type. Genetic analysis indicated that the mutation was controlled by a single recessive nuclear gene. To map the OsSRH1 gene, an F2 population was generated by crossing the mutant Ossrh1 with wild type Kasalath. OsSRH1 was firstly mapped between the microsatellite markers RM3183 and RM193 on chromosome 6 with genetic distance of 0.9 cM and 1.0 cM, respectively. Three new polymorphic STS (sequence-tagged site) markers were developed in the region. OsSRH1 was finally mapped between markers T1757 and T1768 with a distance of 115 kb. 【Conclusion】 The Ossrh1 mutant is controlled by a recessive nuclear gene, which is located on chromosome 6, between T1757 and T1768 with a physical distance of 115 kb.

Cloning and Characteristic Analysis of Cold Stress Transcription Factor LsICE1 from Lettuce and Transformation into Rice

XIANG Dian-Jun, YIN Kui-De, MAN Li-Li, XU Zheng-Jin

Scientia Agricultura Sinica. 2011, 44(21): 4340-4349. doi:10.3864/j.issn.0578-1752.2011.21.002

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【Objective】 Cloning, sequence analysis and transformation into rice with cold stress transcription factor LsICE1 from lettuce were conducted to elucidate the effects of overexpression of LsICE1 on low temperature stress tolerant capacities in rice.【Method】The highly conserved cDNA region of LsICE1 gene from Lactuca sativa L. was isolated by reverse transcription-PCR (RT-PCR) with a pair of degenerate primers, 3′-end and 5′-end were amplified by single oligonucleotide nested PCR (SON-PCR) and then the three cDNA segments were combined and constituted a full-length cDNA sequence of LsICE1 gene. Bioinformatics methods were used to analyze the obtained cDNA sequences and the deduced amino acid sequences. The gene expression levels at 4℃ were analyzed by semi-quantitative RT-PCR (s-qRT-PCR). With constructed plant expressing vector, LsICE1 gene was successfully transferred into rice by Agrobacterium-mediated transgenic technique. The regulation effects of LsICE1 gene with high expression levels on low temperature stress tolerant capacities were evaluated by the comparisons of survival rate and physiological parameters among the transgenic lines and control (CK) after low temperature treatment. 【Result】 Sequence analysis showed that the combined cDNA (designated as LsICE1, GenBank Accession No. HQ848932) fragment length was 1 622 bp containing a full coding region of 1 497 bp encoding 498 amino acid residues. The qRT-PCR result suggested that LsICE1 was differential expression gene under low temperature stress. The homology tree demonstrated that LsICE1 was at the same evolutionary branch with VvICE1. PCR and RT-PCR detection confirmed that LsICE1 gene had been integrated into rice genome. After low temperature stress treatment, compared with control, the transgenic lines with high expression levels of the LsICE1 gene had obvious higher survival rates and proline content. In the meantime, the accumulation rate of relative conductivity and malondialdehyde (MDA) content were much lower. 【Conclusion】 The cold stress transcription factor LsICE1 was firstly cloned from leaf of Lactuca sativa L. with cold tolerance. Overexpression of LsICE1 gene improved low temperature stress tolerant capacities in transgenic rice lines.

Transformation of Wheat with High Molecular Weight Glutenin Subunit Gene 1Bx14

LIU Xiang-Li, JIN Wei-Bo, LIU Jin, ZHAO Hui-Xian, GUO Ai-Guang

Scientia Agricultura Sinica. 2011, 44(21): 4350-4357. doi:10.3864/j.issn.0578-1752.2011.21.003

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【Objective】 The objective of this study is to use genetic transformation of high quality HMW-GS gene 1Bx14 to improve wheat bread-making quality. 【Method】 This investigation, based on the clone of HMW-GS gene 1Bx14 and construction of plant expression vectors, transformed the immature embryo of Mianyang19 by microprojectile bombardment. After selection with hygromycin and tested by PCR, the positive progenies were confirmed by PCR-Southern and Southern blotting. The compositions of high molecular weight glutenin subunit were analyzed by SDS-PAGE.【Result】Six transformed plantlet was obtained from 652 transformed callus, yielding a transformation frequency of 0.92%. The HMW-GS gene 1Bx14 was expressed in some seeds of transgenic plants with the expression of other subunits suppressed in varying degrees. 【Conclusion】The high molecular weight glutenin subunit gene 1Bx14 was transformed into wheat Mianyang 19 and was expressed in some transgenic progenies.

Root Traits Affecting N Absorptive Capacity in Conventional Japonica Rice

YU Xiao-Feng, LI Jin-Qian, TIAN Hao, PENG Bin, ZHANG Yan, WANG Yi, YUAN Qiu-Mei, HUANG Jian-Ye, WANG Yu-Long, DONG Gui-Chun

Scientia Agricultura Sinica. 2011, 44(21): 4358-4366. doi:10.3864/j.issn.0578-1752.2011.21.004

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【Objective】 The objectives of the study were to investigate the evolution trends and diversities of root traits in conventional japonica rice cultivars of different N accumulation types, define the root traits of japonica rice cultivars with high N accumulation, and to provide experimental evidence for genetic improvements of root traits in conventional japonica rice cultivars.【Method】A total of 94 conventional japonica rice cultivars were solution-cultured in 2008 and 2009. Morphological and physiological traits of root, dry weight and N concentration of rice plant, grain yield and its components were measured. Then, the tested rice cultivars were clustered into 6 types based on their N accumulation at maturity by MinSSw method, and the differences in root and other traits between the types were analyzed.【Result】There was a significant difference among all tested cultivars in N accumulation. The highest N accumulation was 2.94 and 2.59 times as the lowest in 2008 and 2009, respectively. The average yields of japonica rice cultivars with high N accumulation were significantly higher than those with low N accumulation. Both growth duration and nitrogen uptake intensity were the main factors influencing N accumulation, but the influence of nitrogen uptake intensity to N accumulation was bigger. There were significant differences in root dry weight per plant, total length of adventitious roots per plant, total root absorption area per plant and root activity absorptions per plant of different types of japonica rice cultivars. The number of adventitious roots per plant and root activity per plant varied in different years. The root traits of cultivars with high N accumulation, including the number of adventitious roots per plant, root dry weight per plant, total length of adventitious roots per plant, total root absorption area per plant, root activity absorptions per plant and root activity per plant, were superior to those with low N accumulation. High accumulation could be reached by improving root dry weight per plant, ratio of shoot to root, total length of adventitious roots per plant and root dry weight per adventitious. 【Conclusion】 There is a significant difference among all tested cultivars in N accumulation. Nitrogen uptake intensity is an important factor for N accumulation. The root traits of cultivars with high N accumulation, including the number of adventitious roots per plant, root dry weight per plant, total length of adventitious roots per plant, the total root absorption area per plant, the root activity absorptions per plant and root activity per plant, are superior to those with low N accumulation, root dry weight per plant, the ratio of shoot to root, the total length of adventitious roots per plant and dry weight per adventitious are the main factors influencing N absorptive capacity.

Study on Canopy Structure and Physiological Characteristics of Super-High Yield Spring Maize

ZHANG Yu-Qin, YANG Heng-Shan, GAO Ju-Lin, ZHANG Rui-Fu, WANG Zhi-Gang, XU Shou-Jun, FAN Xiu-Yan, YANG Sheng-Hui

Scientia Agricultura Sinica. 2011, 44(21): 4367-4376. doi:10.3864/j.issn.0578-1752.2011.21.005

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【Objective】 Canopy structure and canopy functional characteristics of super-high yield spring maize populations were studied to reveal the physiological mechanism of formation of super-high yield, which provided a theoretical basis for cultivation of super-high yield spring maize.【Method】The Jinshan 27 was grown under super-high-yield cultivation (SHY) and normal high-yield cultivation (CK) condition in 2009 and 2010 to assess the indexes of canopy structure and physiological characteristics of super-high yield maize.【Result】Compared with normal high-yield cultivation, the super-high yield spring maize had higher leaf area index (LAI), and three-ear leaves was more obvious after silking stage. Leaf angle of different leaf locations was lower and the leaf direction value was higher than normal high-yield cultivation, and particularly in the three-ear. With the process of the growing period, the difference of photosynthetic potential between the super-high-yield cultivation and the normal high-yield cultivation increased. In the silking stage and milking stage, the difference of the net photosynthetic rate of two cultivation modes was not significant, but canopy photosynthetic ability of super-high cultivation was significantly higher than normal high-yield cultivation. From the silking stage to 40 days, SOD and POD activities were higher than the normal cultivation and MDA content lower than the normal cultivation.【Conclusion】The super-high yield spring maize has higher LAI and population photosynthetic potential, smaller leaf angle and higher leaf direction value, and canopy structure is reasonable. The super-high yield spring maize has stronger SOD and POD activities, lower the MDA content, higher net photosynthetic rate and stronger photosynthetic potential. So under the reasonable cultivation technique condition, collaborative gain can be obtained from super-high-yield spring maize community structure and individual function.

Changes of mRNA Expression of Five Defense Genes of Cotton Response to Damages Caused by Different Phytophagous Insects

LI Jing, ZHANG Shuai, CUI Jin-Jie

Scientia Agricultura Sinica. 2011, 44(21): 4377-4384. doi:10.3864/j.issn.0578-1752.2011.21.006

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【Objective】The objective of this study is to understand the role of 5 defense protein genes defensing the phytophagous pests in cotton.【Method】Using the real-time quantitative PCR, the expression changes of the polyphenol oxidase (PPO), chloroplast Cu/Zn superoxide dismutase, ATP synthase β subunit, light-harvesting protein complex Ⅱ and heat shock protein (Hsp70) genes, which were damaged by Helicoverpa armigera, Spodoptera litura, Spodoptera exigua and mechanical damage for 0 (control), 6, 12, 24, 48, 60 h, respectively, were studied. 【Result】 In the 4 damage treatments, the polyphenol oxidase, heat shock protein and chloroplast Cu/Zn superoxide were stronger in response to insect feeding damage, but the light-harvesting protein complex Ⅱ was more sensitive to the mechanical damage, and ATP synthase β subunit was stronger in response to the insect feeding damage and mechanical damage. PPO responded rapidly to the H. armigera infestation, while the reaction to the S. exigua infestation was rather slowly, and without specific answer to the damage of S. litura. After 4 treatments, Hsp70 expression had a significant change, and it increased larger against the damages caused by H. armigera and S. exigua. ATP synthase β subunit was down-regulated to mechanical damage and S. litura. While after damage caused by H. armigera and S. exigua the expression was up-regulated. The light-harvesting protein complex Ⅱ was down-regulated except the damage caused by H. armigera. Chloroplast Cu/Zn superoxide was down-regulated when damaged by machine and S. litura but it up-regulated to the H. armigera and S. exigua, and it responded stronger to the damage caused by H. armigera than S. exigua.【Conclusion】The response of the cotton to different insect damages was different and with a certain specificity.

Resistance Status of Myzus persicae (Sulzer) (Hemiptera: Aphididae) Populations to Pesticide in Beijing

GONG Ya-Jun, WANG Ze-Hua, SHI Bao-Cai, KANG Zong-Jiang, ZHU Liang, GUO Xiao-Jun, LIU Jian-Hua, WEI Shu-Jun

Scientia Agricultura Sinica. 2011, 44(21): 4385-4394. doi:10.3864/j.issn.0578-1752.2011.21.007

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【Objective】 The objective of this study is to survey the resistance level of peach aphid Myzus persicae (Sulzer), one of the most serious pest in Beijing area. 【Method】 Bioassay of five frequently used pesticides to six field populations and a sensitive population was conducted, the kdr resistance was detected by bi-PASA PCR method, and the esterase and acetylcholinesterase activities of this pest were tested. 【Result】 The results show that both the six field populations, in Tongzhou, Shunyi, Daxing, Haidian, Yanqing and Mentougou and the sensitive population developed resistance to beta-cypermethrin. The proportion of resistant homozygote was higher than 90% in all populations except for Yanqing and Mentougou. Mentougou, Tongzhou and Yanqing populations developed resistance to chlorpyrifos and imidacloprid with resistance ratio of 2.05-4.24 and 32.03-41.27, respectively. All of the field populations were sensitive to abamectin and emamectin benzoate (the resistance ratio was 0.19-1.44), except for the Daxing population (the resistance ratio was 3.45 and 2.82, respectively) and Haidian population to abamectin (the resistance ratio was 2.66). There was a significant positive correlation between the esterase activity and resistance ratio to chlorpyrifos and imidacloprid, while there was a negative correlation between acetylcholinesterase activity and resistance ratio of chlorpyrifos and imidacloprid. 【Conclusion】 The peach aphid in Beijing area developed resistance to nearly all frequently used pesticides tested in this study. The beta-cypermethrin should not be used, and the chlorpyrifos should be avoided, and abamectin, emamectin benzoate and imidacloprid could be used alternatively.

Effects of Different Fertilization and Mulching Cultivation Methods on Yield and Soil Water Use of Winter Wheat on Weibei Dryland

XUE Cheng, WANG Chao-Hui, LI Fu-Cui, ZHAO Hu-Bing, ZHOU Ling, LI Xiao-Han

Scientia Agricultura Sinica. 2011, 44(21): 4395-4405. doi:10.3864/j.issn.0578-1752.2011.21.008

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【Objective】 Research on effects of fertilization and mulching cultivation patterns on yield and water use of winter wheat is recognized to be of great significance in increasing crop yield and water and nutrient efficiency on Weibei dryland.【Method】Field experiments were carried out to study the effects of recommended N fertilization based on soil test, topdressing, ridge-mulching and furrow seeding, and covering soil surface by retention of wheat straw during summer fallow on winter wheat yield, biomass, harvesting index, water use efficiency and annual changes of soil water.【Result】 Results showed that compared to local farmers’ cultivation mode (apply all the fertilizers to soil once before seeding), topdressing of partial N fertilizer (25% of total) in dry-land region increased winter wheat yield by 6%-14% and WUE by 7%-10%, with WUE reaching 12.2 kg•hm-2•mm-1 to 13.6 kg•hm-2•mm-1; ridge-mulching and furrow seeding combined with N reduced topdressing increased winter wheat yield by 15%-41% and WUE by 10%-30%, and the WUE were as high as 12.2 kg•hm-2•mm-1 to 16.5 kg•hm-2•mm-1. Optimizing nitrogen fertilizer application by 1/4 nitrogen fertilizer being topdressed and at the same time using the ridge-mulching and furrow seeding was found to be able to enhance deep soil water usage by winter wheat, increase water content of winter wheat at heading stage and then enhance the biomass and harvesting index at harvest. This method led to a higher soil water consumption over the whole growing season, but the water use efficiency was also increased due to much more increase of grain yield. However, only reducing nitrogen input did not increase the water use efficiency. Nitrogen reduced topdressing combined with ridge-mulching and furrow seeding also increased soil storage of rainfall water during summer fallow and the summer fallow efficiency, by covering furrow soil surface by retention of wheat straw and keeping the ridge mulched plastic film during summer fallow. This method achieved annual soil water balance and was proved to be able to sustainablely increase winter wheat yield.【Conclusion】Optimizing nitrogen application combined with ridge-mulching and furrow seeding was showed to be the cultivation and fertilization method to increase yield and water use efficiency for winter wheat growing in Weibei dryland area on the Loess Plateau.

Study on Nitrogen Fertilizer Effect and Optimum Fertilizer Rate for Transplanting and Direct-Seeding Rapeseed

WANG Yin, LU Jian-Wei, LI Xiao-Kun, LI Ji-Fu, LIU Peng-Peng, XU Wei-Ming, YANG Yun-Qing

Scientia Agricultura Sinica. 2011, 44(21): 4406-4414. doi:10.3864/j.issn.0578-1752.2011.21.009

Abstract ( 749 )

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【Objective】In order to provide a scientific basis for rapeseed fertilization, the effects of nitrogen fertilization on growth and yield of transplanting and direct-seeding rapeseed were studied to seek the characteristics of nitrogen nutrition for direct-seeding rapeseed, and to compare and understand the difference of nitrogen fertilizer effect and optimum fertilizer rate between the transplanting and direct-seeding planting patterns.【Method】A field experiment of nitrogen fertilization on transplanting and direct-seeding rapeseed was conducted in Shayang of Hubei during 2009-2010, field surveys and yield analysis were taken, and the optimum nitrogen fertilizer rate was determined based on the fertilizer effect model. 【Result】 Due to the different planting patterns, the plant morphology and growth characteristics were quite various for transplanting and direct-seeding rapeseed. Transplanting rapeseed developed better in all aspects than direct-seeding rapeseed, the advantage of individual plant was obvious, but the direct-seeding rapeseed had group advantage, and the yield level was similar to that of transplanting rapeseed. Nitrogen fertilizer promoted effectively growth and increased significantly yield of both transplanting and direct-seeding rapeseed. Meanwhile, effects of nitrogen fertilizer on rapeseed were different in two planting patterns, and the growth and yield formation of transplanting rapeseed were more significantly influenced by nitrogen fertilizer. Direct-seeding rapeseed had a large root group, could uptake more nitrogen from soil, and the requirement to exogenous nitrogen was lower than that of transplanting rapeseed. The optimum fertilizer rates of transplanting and direct-seeding rapeseed in this experiment were 228.4 kg•hm-2 and 130.3 kg•hm-2, respectively.【Conclusion】 The plant morphology, growth and nitrogen effect of transplanting and direct-seeding rapeseed are obviously different. Compared to transplanting rapeseed, direct-seeding rapeseed requires less nitrogen fertilizer, and has high economic benefit when their yield are similar. Therefore, the direct-seeding rapeseed has better prospects for rapeseed production.

Evaluation and Application of the SSR Loci in Apple Genome

GUAN Ling, ZHANG Zhen, WANG Xin-Wei, XUE Hua-Bai, LIU Yan-Hong, WANG San-Hong, QIAO Yu-Shan

Scientia Agricultura Sinica. 2011, 44(21): 4415-4428. doi:10.3864/j.issn.0578-1752.2011.21.010

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【Objective】 In order to provide a theoretical and practical foundation for the genetic analysis of Rosaceae fruit trees which based on the SSR markers, the SSR loci from apple (Malus × domestica Borkh. ‘Golden Delicious’) genome was analyzed.【Method】The genome data of apple ‘Golden Delicious’ was downloaded from the NCBI website and the MISA software was used to analyze the distribution of genome SSR loci. We designed sixty-eight primers, which 4 primers from each chromosome according to the searching results of the SSR loci, were designed and the 10 apple cultivars and F1 progeny of pear were utilized to examine the application and transferability of designed primers, respectively.【Result】The perfect repeat sequences were found that it is the main form of the SSR sequences type and the total number of SSR loci is 163 426 in apple genome. There will be one SSR loci from every 3.22 kb on average. The distribution of the mononucleotide, dinucleotide and trinucleotide repeat motifs in the chromosome standard were stable relatively, whereas the picture of tetranucleotide, pentanucleotide and hexanucleotide repeat motifs were not. The largest proportion of the SSR loci is the mononucleotide and the dinucleotide repeat motifs, they possessed 91.67% of the total SSRs in the whole genome. As scanned for the mononucleotide repeat units, base A/T is the mainly proportion, the base pair AT/TA is the domination in the dinucleotide repeat units. There are 62 and 37 primers could amplify the predicted and polymorphic fragments in apple among 68 designed primers, separately. Whereas, in pear, there are only 16 polymorphic primers in the 40 primers which can be amplified the same size fragments as predicted.【Conclusion】Some distribution raws of SSRs in the apple genome were found. The results that SSR loci in the closer genetic relationship among species are highly conserved and can be used in the following research were demonstrated preliminarily. It is meaningful to develop SSR loci from genomic data for the application of relative genetic analysis.

Molecular Classification of Jujube Witches’ Broom (JWB) Associated Phytoplasma from Ziziphus jujuba Mill. ‘Zanhuangdazao’

YANG Hai-Xu, WANG Yang, ZHAO Yan-Lin, ZHAO Jin, LIU Meng-Jun

Scientia Agricultura Sinica. 2011, 44(21): 4429-4437. doi:10.3864/j.issn.0578-1752.2011.21.011

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【Objective】 Jujube Witches’ Broom (JWB) is a serious disease caused by phytoplasma. In this paper, the taxonomic status of JWB-associated phytoplasma from Ziziphus jujuba Mill. ‘Zanhuangdazao’，which is the only natural triploid cultivar in Chinese jujube, was identified.【Method】16S rDNA gene was amplified by using specific conservative primers and the nested-PCR primers, then the PCR product was cloned and sequenced. Homology analysis, dendrogram and virtual RFLP were also obtained by using related software. 【Result】 One set of the conserved primers was designed to amplify a 1 850 bp fragment (GenBank GU184180) which included 16S rDNA (1 529 bp), adjacent spacer sequence (264 bp) and partial sequence of 23S rDNA (57 bp) by PCR from total DNA extracted from diseased Ziziphus jujuba Mill. ‘Zanhuangdazao’. Nucleotide sequencing of the amplified fragment indicated that JWB-associated phytoplasma from Ziziphus jujuba Mill. ‘Zanhuangdazao’ shared nucleotide similarity about 87% to 98% with other phytoplasmas from data of GenBank, and a maximum similarity at 98% with Elm yellows（EY）phytoplasma. A phylogenetic tree based on 16S ribosomal DNA sequences was constructed. The result of virtual RFLP showed a significant difference among JWB-associated phytoplasma from Ziziphus jujuba Mill. ‘Zanhuangdazao’ and 4 subgroups. The blast result of tuf also showed that JWB-associated phytoplasma from Ziziphus jujuba Mill. ‘Zanhuangdazao’ (JN001985) shared nucleotide similarity about 52.3% to 76.7% with 4 subgroups. 【Conclusion】 JWB-associated phytoplasma from Ziziphus jujuba Mill. ‘Zanhuangdazao’ was clustered into the elm yellows group (16Sr V) phytoplasma, and it shared the highest similarity with the B subgroups. Its taxonomic status is consisting with those diploid cultivars.

AHP-Based Screening of Traditional Potted Chrysanthemum for Industrialized Production

ZHANG Ya-Qiong, ZHANG Wei, DAI Si-Lan, JI Yu-Shan, HE Jing

Scientia Agricultura Sinica. 2011, 44(21): 4438-4446. doi:10.3864/j.issn.0578-1752.2011.21.012

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【Objective】The aim of the present study was to establish a synthetic system for assessing the industrial value of traditional chrysanthemum varieties, and to offer a theoretical support for selection and application. 【Method】 Pot-culture experiments were conducted to observe 19 indexes of 32 traditional potted chrysanthemum cultivars. A comprehensive evaluation system was established by using AHP method., which considers the ornamental traits, variety resistance and cultivation process. 【Result】 Finally, the weight of 19 evaluating factors was calculated, including flower color, seedling growth vigor, plant height, bud germination capacity, the natural flowering time, and drought resistance. The weight of each effecting factor was 0.1469, 0.1206, 0.0959, 0.0815, 0.0815, and 0.0679. According to the comprehensive scores, cultivars were divided into 4 grades: excellent, good, general, and poor, of which the excellent ones can be applied to industrial production. 【Conclusion】 Seven suitable chrysanthemum cultivars were selected for large-scale production. This study will provide a reasonable exploitation of precious traditional chrysanthemum resources.

Bio-Control Effect of Combining Bacillus subtilis fmbj with 2-Deoxy-D-Glucose on Rhizopus stolonifer

ZHOU Xiao-Hong, LU Zhao-Xin,LU Feng-Xia , BIE Xiao-Mei

Scientia Agricultura Sinica. 2011, 44(21): 4447-4453. doi:10.3864/j.issn.0578-1752.2011.21.013

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【Objective】 This study aims to enhance the biocontrol effect of antagonistic Bacillus subtilis fmbj on peach fruit soft rot disease caused by Rhizopus stolonifer.【Method】The synergitic effect of this antagonistic bacterium in combination with different concentrations of 2-Deoxy-D-Glucose (2-DOG) on pathogenic R. stolonifer, and the effect of 2-DOG on growth of both antagonistic bacterium and pathogen were tested in this work. 【Result】 The results in vitro showed that R. stolonifer could be completely inhibited by 0.3 mg•mL-1 of 2-DOG, while B. subtilis fmbj stia grew and gathered abundantly in the wound of peach fruit at 20 mg•mL-1 of 2-DOG and presented a high 2-DOG-resistance. In vivo the results indicated that 4 mg•mL-1 of 2-DOG combined with 3.9×107CFU/mL of B.subtilis fmbj totally protected peach fruit from decay, but when only 3.9×108CFU/mL of B. subtilis fmbj or 2-DOG was used, the soft rot disease of peach fruit would occur and the disease incidence was respectively 30% and 35%.【Conclusion】Combination of B. subtilis fmbj and 2-DOG showed a more effective control on R. stolonifer than applying the B. subtilis fmbj or 2-DOG alone. This research established a significant bio-control method for peach fruit post harvest preservation.

Effect of Irradiation on the Molecular Weight and Structure and Rheological Behaviour of Xanthan Gum

LI Yan-Jie, HA Yi-Ming, WANG Feng, LI Yong-Fu

Scientia Agricultura Sinica. 2011, 44(21): 4454-4463. doi:10.3864/j.issn.0578-1752.2011.21.014

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【Objective】 The effects of irradiation dose on the molecular weight, molecular weight distribution, structures and rheological behaviour of xanthan gum were investigated for the purpose of applying irradiation technique to molecular modification of xanthan gum and even other polysaccharides. 【Method】 Xanthan gum was irradiated in dry state at different doses (0-400 kGy) of 60Co γ-rays to investigate the changes of the molecular weight, molecular weight distribution, structures and rheological behaviour of irradiated xanthan gum by using gel permeation chromatography (GPC), X-ray diffraction (XRD), fourier-transform infrared spectra (FTIR), ultraviolet-visible spectral (UV-vis) and rheometer. 【Result】 Results showed that the molecular weight and crystallinity of xanthan gum increased at 10 kGy, then decreased gradually with increasing irradiation dose. Contrary to it, molecular weight distribution of irradiated xanthan gum decreased at 10 kGy, then increased gradually to maximum value at 50 kGy, and then decreased with irradiation dose. FT-IR spectra and XRD indicated that γ-irradiation introduced no significant changes into the structure and crystal texture but UV spectra showed a distinct absorption peak at about 265 nm, increasing with irradiation dose, which was attributed to the formation of carbonyl groups or double bond. The relationship between apparent viscosity of xanthan gum solution and shearing rate, shear time and temperature were varied significantly. 【Conclusion】 γ-irradiation can act simultaneously on crystallization area and amorphous area of xanthan gum, and cause polymerization or degradation of xanthan gum molecule, thus the molecular weight and molecular weight distribution, and then the rheological behaviour of irradiated xanthan gum were obviously changed.

Effects of Feeding Levels of a Milk Replacer on Digestion and Metabolism of Nutrients, and Serum Biochemical Indexes in Lambs

YUE Xi-Xin, DIAO Qi-Yu, MA Chun-Hui, DENG Kai-Dong, TU Yan, JIANG Cheng-Gang, DU Hong-Fang

Scientia Agricultura Sinica. 2011, 44(21): 4464-4473. doi:10.3864/j.issn.0578-1752.2011.21.015

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【Objective】This study was performed to investigate the effects of different feeding levels of a milk replacer on growth performance, nutrient digestion and metabolism, and serum biochemical parameters in early weaned lambs. 【Method】Twenty seven newborn crossbred F1 lambs (Dorset×Thin-Tailed Han sheep) were randomly divided into 3 groups and each fed with a milk replacer at 1.0% (L), 1.5% (M) or 2.0% (H) of BW. Digestion and metabolism trials were carried out from 50 to 60 and from 80 to 90 d of age, respectively. Blood metabolites were determined at 50 and 90 d of age. 【Result】 The growth performance of lambs was improved as the feeding levels of the milk replacer increased, significant differences in the BW and BL existed among three treatments (P＜0.05). As feeding levels increased, the digestibility of DM, OM, GE, N, EE, Ca and P rose. The digestibility of DM, GE, N, EE, Ca and P in the L group was significantly lower than that in the H group (P＜0.05), but the retention of N in the H group was only 70.9%, which was significantly lower than that in the L group (78.7%) (P＜0.05). At 50 d of age, no significant differences in the serum concentration of TP, BUN, GLU, CHOL and TG were detected among the groups(P＞0.05), but the activity of serum ALP in lambs from the L or M group was significantly lower than that from the H group (P＜0.05). At 90 d of age, the serum concentration of CHOL in the H group was significantly higher than that in the L group (P＜0.05). 【Conclusion】 A proper feeding level of milk replacers significantly improved the growth performance, and nutrient digestion and metabolism. The lambs of 20-50, 50-70 and 70-90 d of age were suggested to be fed at 2.0%, 1.5% and 1.0% BW, respectively.

Comparison of Difference and Ontogenetic Expression of EAATs mRNA in the Small Intestine of Broiler Chick Embryo

LI Xiang-Guang, YAN Hui-Chao, ZENG Pei-Ling, ZHANG De-Xiang, WANG Xiu-Qi

Scientia Agricultura Sinica. 2011, 44(21): 4474-4480. doi:10.3864/j.issn.0578-1752.2011.21.016

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【Objective】The objective of this study was to compare the difference and ontogenetic expression of glutamate transporters (EAAT2 and EAAT3) mRNA in small intestine of broiler chick embryo. Two breeds were selected, one was Wens Yellow-Feathered Chicken (WYFC, a Chinese local breed which grows slowly and marketed age for female is over 100 days) and the other was White Recessive Rocks Chicken (WRRC). 【Method】 Ninety-six fertilized eggs of each breed which had a similar weight were assigned into 6 groups for hatching. Sixteen small intestinal samples from each group were collected on embryonic days 9 (E9), 12 (E12), 14 (E14), 17 (E17), 19 (E19) and day of hatch (DOH) after the eggs were weighed. The expressions of EAATs mRNA were determined using real-time RT-PCR by relative quantification method. 【Result】The resuts showed that weight of embryonated egg on E9, E12, E14, E17 and E19, and hatchling of WRRC was significantly higher than that of WYFC (P＜0.01). Ontogenetic patterns of EAAT2 mRNA were similar in the 2 breeds，which downregulated from E9 to E14 and upregulated on E17, followed by an downregulation to DOH. In comparison between the two breeds, there was a highly significant difference (P＜0.01) on E12, E17, E19 and DOH and a significant difference (P＜0.05) on E14. Ontogenetic patterns of EAAT3 mRNA were upregulated along with embryonic development in both 2 breeds, which showed a highly significant difference (P＜0.01) on E19 and a significant difference (P＜0.05) on E12. The abundance of EAAT2 and EAAT3 mRNA in the small intestine of WYFC was higher than that of WRRC and affected by embryonic days. There was an interaction of breed×embryonic day on the both EAAT2 and EAAT3 mRNA abundance. 【Conclusion】 The expression of EAATs mRNA differed in breeds as well as embryonic days. Ontogenetic patterns of EAAT2 and EAAT3 mRNA were different.

Influence of Infusing Amino Acids into the External Pudendal Artery on Nutrient Uptake in the Mammary Gland of Dairy Goats

WANG Qiang, AO Chang-Jin, GA 尔Di, LU De-Xun, GAO Min, DUAN Bin, FENG Zi-Qi

Scientia Agricultura Sinica. 2011, 44(21): 4481-4487. doi:10.3864/j.issn.0578-1752.2011.21.017

Abstract ( 609 )

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【Objective】 An experiment was conducted to study the effects of different balance models of amino acids in the artery blood flow by infusing amino acids into the external pudendal artery on nutrient uptake in the mammary gland of dairy goats. 【Method】 Three dairy goats at 2-3-year old of age with similar body weight and milk yield were intubated in the external pudendal artery and the abdominal subcutaneous vein, in this study. Different balance models of amino acids in the blood flow were made by infusing amino acids into the external pudendal artery. Arterio-venous plasma, at the start and the end of infusion, were collected to measure the changes of milk protein precursors (MPP), milk fat precursors (MFP) and milk lactose precursors (MLP) concentrations as well as nutrients uptake in the mammary gland. 【Result】 The uptake of MPP and MFP in the mammary gland was step up after infusing amino acids into the external pudendal artery (P＜0.05). Compared with the control group, the uptake of MLP by the mammary gland was increased after infusing, but there was no significant difference in the ideal amino acids model group (P＞0.05), meanwhile the difference was significant in the balance model group (P＜0.05). The milk production and milk content of the dairy goats were significantly different in the two groups (P＜0.05) compared with the control group. 【Conclusion】 Under the conditions of the experiment, the amino acids balance could change the uptake of milk components precursors in the mammary gland and in favor of the synthesis of milk. The uptake of milk components precursors in the mammary gland was optimum when the amino acid model was arrived at the ideal balance level (AABI=0.972).

Advances in Research of Silk Gland Bioreactor of piggyback –Mediated Transgenic Silkworm

ZHONG Bo-Xiong, WEI Hao, ZHUANG Lan-Fang

Scientia Agricultura Sinica. 2011, 44(21): 4488-4498. doi:10.3864/j.issn.0578-1752.2011.21.018

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This paper reviewed three key steps of recombinant protein expression by silk gland bioreactor of piggyBac- mediated transgenic silkworm. Firstly, the efficient insertion of foreign gene into the genome. Secondly, high-efficiency detection and identification of the transgenic silkworm. Finally, the expression and purification of the active recombinant protein. Meanwhile,it also introduced the advances in research of this kind of bioreactor. The review provided effective information for the future researches.

Development of Loop-Mediated Indirect PCR for Simultaneously Detecting Three Species of Viruses in Pigs

ZHENG Ming, BIAN Chuan-Zhou, WANG Lao-Qi

Scientia Agricultura Sinica. 2011, 44(21): 4499-4507. doi:10.3864/j.issn.0578-1752.2011.21.019

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【Objective】 The aim of this study is to establish a method of loop-mediated indirect PCR assay for simultaneous identification of porcine circovirus type 2 (PCV2), classical swine fever virus (CSFV) and porcine reproductive and respiratory syndrome virus (PRRSV) in pigs. 【Method】 According to the nucleotide sequences of PCV2, CSFV and PRRSV from GenBank, three pairs of specific probes were designed. By PCR, the Lectin gene fragment of soybean was labeled with different probes to be used as reporter genes aiming to the nucleotide sequences of PCV2, CSFV and PRRSV, respectively. After hybridizing with the target gene, gap filling and cyclizing, these probe-labeled reporter genes were amplified by reverse PCR with a pair of primers to detect the three species of viruses indirectly. The loop-mediated indirect PCR assay was developed, and the specific PCR products were 564 bp for PCV2, 434 bp for CSFV and 338 bp for PRRSV, respectively. The assay will be useful for the specific detection of the three species of viruses, not only for single virus but also for multiple viruses. 【Result】 The specificity and sensitivity of the loop-mediated indirect PCR assay were analyzed for single virus and multiple viruses. The results showed that the specificity was high, and no amplification was achieved to the other pathogeneses. The detection limits of the loop-mediated indirect PCR assay for multiple viruses was 0.8 pg?μL-1 for PCV2, 25 pg?μL-1 for CSFV and 6.2 pg?μL-1 for PRRSV, respectively, which was the same with the results of single virus detection. Twenty clinical samples were comparatively detected. The data showed that the results of the loop-mediated indirect PCR assay, not only for single virus but also for multiple viruses, were in accordance with the results of conventional PCR.【Conclusion】 The loop-mediated indirect PCR developed in this study is a simple, fast and specific method for detecting PCV2, CSFV and PRRSV in clinical samples, and can be used to detect all these three species of viruses at the same time.

Establishment of ELISA Based on Recombinant Protein MSG1 for the Detection of Mycoplasma suis Antibody

LIU Yong-Xia, LIU Jian-Zhu, CHENG Zi-Qiang, ZHOU Dong, WANG Zhen-Yong, LIU Hai-Tao, WANG Lin, CHAI Tong-Jie

Scientia Agricultura Sinica. 2011, 44(21): 4508-4515. doi:10.3864/j.issn.0578-1752.2011.21.020

Abstract ( 671 )

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【Objective】 An enzyme-linked immunosorbent assay (ELISA) system based on the polyclonal antibody against the adhesion protein MSG1 which was coded by the g1 gene of Mycoplasma suis(M. suis) was established, and was assessed as an effective method for detection of M. suis in swine. 【Method】 The MSG1-pET28c_E.coli BL21 was induced to express the MSG1protein of M. suis, and broken by ultrasound, the aim protein was purified by nickel affinity chromatography. The immunogen that was made of this purified recombinant protein was vaccinated to the mice to produce the polyclonal antibody. The polyclonal antibody and the recombinant protein were used to build an ELISA to detect M. suis, and the sensitivity, specificity, coincidence and repeatability of this method was analyzed, respectively. 【Result】 The polyclonal antibody was obtained whose titer had reached an adequate level. The infection rate of M. suis was 46.25% through the built ELISA method, the positive samples of them could hinder the polyclonal antibody from integrating with the MSG1protein markedly and didn’t react with some other antigens. The sensitivity and specificity values reached 95.92% and 97.06%, respectively, and a higher detection rate was confirmed through the ELISA method comparing with the IHA method. 【Conclusion】 The results show that the antigenicity of the protein MSG1 was satisfactory. This ELISA system had a higher sensitivity, specificity, coincidence and stability for the serodiagnosis of M. suis. A desirable result would be obtained from the detection of M. suis.

Isolation and Identification of Piglets’ Small Intestinal Mucous Membrane Epithelial Cells

ZHOU Chuan-Li, LIU Zheng-Zhu, YU Ying, ZHANG Qin

Scientia Agricultura Sinica. 2011, 44(21): 4516-4524. doi:10.3864/j.issn.0578-1752.2011.21.021

Abstract ( 978 )

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【Objective】 To elucidate the pathogenic mechanism of enterotoxigenic Escherichia coli F18 (ETEC F18), 3 cell lines with GG, GA, AA genotypes of the candidate gene FUT1 at CDS 307 (G→A) were established using piglets’ small intestinal mucous membrane.【Method】In this study, fetal rats and neonatal piglets were firstly used as preliminary experiment materials to compare the effectiveness of two digestion methods for isolating intestinal mucous membrane cells. The first digestion method was that the fetal rat intestine was cutted mechanically and then digested with prepared mixture of collagenase XI and dispase I. The senod one was that the small intestine of neonatal pig was directly filled with the mixture. Removal of the fibroblast-cell- contamination is one of the troublesome things during the process of intestinal cells primary culture in vitro. In this study, purification of the epithelium was facilitated by using a simple partial digestion method upon the contamination of the fibroblast cells. Finally, the purified primary small intestine epithelial cells were identified using electron microscopy and CK18 immunofluorescence staining.【Result】The results showed that the second digestion way was better than the first one. The neonatal Large White that was born within 12 h was picked and its small intestine was cutted into segments after laparotomizing. Isolation of the epithelia and preservation of its three-dimensional integrity was achieved via collagenase/dispase digestion technique. The photographs of electron microscopy and CK18 immunofluorescence staining showed that the purity of the epithelial cells was above 90%. The entire period of growing pig small intestinal epithelium in primary cultures showed that before the seventh generations of sub-culturing the cells grew well, which showed the typical feature of epithelial cells and the monolayer was pavement-like. After the nineth generations, these untreated cells reached arrest of growth and vacuolization.【Conclusion】Small intestinal epithelial cells with GG and GA genotypes of FUT1 gene were primarily cultured in vitro. In the present study, an ideal method for isolating and culturing epithelial cells of piglets’ small intestinal mucous membrane was established, which laid a good foundation for establishing cell lines of piglet epithelial cell.

Analysis on Dynamic and Pattern of Land Use/Cover Change in Guanzhong Area

HAO Hui-Mei, HAO Yong-Li, REN Zhi-Yuan

Scientia Agricultura Sinica. 2011, 44(21): 4525-4536. doi:10.3864/j.issn.0578-1752.2011.21.022

Abstract ( 703 )

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【Objective】Understanding the process and pattern of regional land use and land cover change is essential for intensive and highly efficient，scientific and rational utilization of land resources.【Method】Based on technology of remote sensing (RS) and geographical information system (GIS), various land-use change models such as Markov transfer matrix model，amendatory land use dynamic model as well asland use degree change model were applied to simulate and analyze the scenario of land use changes from 1990 to 2007 in Guanzhong Area.【Result】The results showed that the land use change in Guanzhong Area was obvious and complicated. And mutual inverse of land use transfer among arable land，forest land and grasslands was happened almost simultaneously in space，especially during the former period (1990-2000). During the latter period，however，land use change was more orderly and stable. The amount of arable land changed into construction land from 1990 to 2007 was 183.3 thousand hm2，and most of them happened in Guangzhong basin area, and during the latter period. Index of amendatory land use dynamic can indicate intensity of land use changes，which also could be used to compare rates of land use changes in different districts and to imply the order degree of land use change in some area during certain period. 【Conclusion】The land use policy and economic benefits are the main drivers of regional land use change. To strengthen protection of arable land in the central Shaanxi basin , and to stabilize and promote ecological restoration and construction in the North Wei plateau and Qinling-Guanshan mountains are key links of land utilization in the future.

Starch Granule Size Distribution in Storage Roots of Different Types of Sweetpotato Cultivars

SHI Chun-Yu, YAO Hai-Lan, ZHANG Li-Ming, LIU Hong-Juan, ZHANG Chao, LIU Gui-Ling

Scientia Agricultura Sinica. 2011, 44(21): 4537-4543. doi:10.3864/j.issn.0578-1752.2011.21.023

Abstract ( 738 )

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【Objective】 An experiment was conducted to clarify the starch granule size distribution and the relationship between starch granule size and starch quality properties in storage roots of different types of sweetpotato cultivars. 【Method】 Six starchy sweetpotato cultivars, five edible sweetpotato cultivars, and one dual-purpose sweetpotato cultivar were planted at Taian experimental site in Shandong Province, with randomized block design in 2009-2010 growing season. The volume distribution and number distribution of starch granule, and their relationship to the content of total starch and its components in storage root were determined. 【Result】The starch granule in storage root was 0.39-55.14 µm in diameter, containing smaller type（diameter＜3.36 µm）, mid-type（diameter 3.36-19.76 µm）and larger type（diameter＞19.76 µm）granules. The distribution frequency showed typical two-peak curve in starch granule volume and number, and the grain diameters were all equal to 3.36 µm. The volume of smaller type granule accounted for 9.8%-18.5% of the total starch granule, and the number of smaller type granule accounted for 97.7%-99.1% of the total starch granule. The volume percentage of ＜3.36 µm starch granule and the number percentage of ＜1.00µm starch granule were higher in edible sweetpotato than in starchy sweetpotato. The contents of total starch , amylose and amylopectin were negatively correlated with the volume percentage of smaller type（r=-0.772**, -0.730**, -0.774**）and middling type（r=-0.723**, -0.715**, -0.712**） starch granules, respectively, but positively correlated to larger type（r=0.746**, 0.729**, 0.738**） starch granule. The ratio of amylopectin to amylose was positively correlated with the volume percentage of smaller type（r=0.716**）and middling type（r=0.740**） starch granules, respectively, but negatively correlated to larger type（r=-0.745**） starch granule. 【Conclusion】The rates of small starch grains in storage root of edible sweetpotato were higher, but the rates of big starch grains in storage root of starchy sweetpotato were higher.

Yield Increase of Smash-Ridging Cultivation of Sugarcane

WEI Ben-Hui, GAN Xiu-Qin, SHEN Zhang-You, NING Xiu-Cheng, LU Liu-Ying, WEI Guang-Po, LI Yan-Ying, HU Bo, LIU Bin, WU Yan-Yong

Scientia Agricultura Sinica. 2011, 44(21): 4544-4550. doi:10.3864/j.issn.0578-1752.2011.21.024

Abstract ( 554 )

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【Objective】 The objective of the experiment is to compare the effect of smash-ridging cultivation of sugarcane on yield increase with traditional cultivation method and to provide a basis for the smash-ridging cultivation of sugarcane. 【Method】 Sugarcane varieties ROC22 and Liucheng 03-1137 were planted in different places by smash-ridging and traditional cultivation methods, and the roots, green leaf, cane stem characters, yield, quality, bamboo shoots buds number and so on were measured. 【Result】 Compared to traditional cultivation, sugarcane cultivated with smash-ridging method, the fresh weight of roots increased by 115.05%-146.48%, the number of complete expanded green leaf (functional leaves) increased by 14.65%-19.35%, the cane stem products increased by 21.91%-27.35%, the cane sucrose contents and juice sucrose contents increased by 3.81%-5.17% and 3.63%-5.75%, respectively. juice reducing sugar contents reduced by 5.50%-9.76% the bamboo shoots buds number increased by 47.64%-197.70%. 【Result】 Planting sugarcane by smash-ridging promoted the development of roots, increased the functional leaves, improved yield, and quality, and increased the bamboo shoots buds number.

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