Table of Content

12 May 2012, Volume 38 Issue 05

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REVIEW

Molecular Mechanism of Plant Defense against Virus Attack

HOU Jing,LIU Qing-Qing,XU Ming-Liang

Acta Agron Sin. 2012, 38(05):  761-772.  doi:10.3724/SP.J.1006.2012.00761

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Viral diseases of plants seriously threaten the crop productivity. Many virus resistance genes are reported to play roles in restraining viral replication and preventing virus movement. The viral replication is a complex process which depends on virus-encoded proteins, host factors, and their interactions. Many host factors are actively engaged in viral replication, e.g. eukaryotic translation initiation factor 4E (eIF4E) and 4G (eIF4G), and plant endomembrane systems. The loss-of-function or conformational changes of these host factors may inhibit viral replication. Furthermore, thioredoxin can regulate cellular redox state to restrain viral replication. Virus movement involves cell-to-cell movement and long distance movement. Hypersensitive cell death is trigged through the perception of a pathogen avirulence factor (Avr) by the cognate plant resistance protein (R protein) to limit the viral cell to cell movement. Dominant plant R genes, characterized by TIR-NBS-LRR or CC-NBS-LRR, are generally responsible for such kind of defense response. There are many factors associated with the long distance virus movement, but only polymerized RTM protein in phloem was identified to limit viral long distance movement. In addition, RNA silencing also actively functions as an antiviral defense response. This review is aimed to summarize various mechanisms of plant defense against virus attack, and to analyze possible implementations of MAS, TILLING, and transgenic technologies in the improvement of virus disease resistance in crops.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Development and Characterization of SN1 Transgenic Wheat Plants with Enhanced Resistance to Rhizoctonia cerealis and Bipolaris sorokiniana

WANG Jin-Feng,DU Li-Pu,LI Zhao,HUANG Su-Ping,YE Xing-Guo,FENG Dou,ZHANG Zeng-Yan

Acta Agron Sin. 2012, 38(05):  773-779.  doi:10.3724/SP.J.1006.2012.00773

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SN1 is an anti-microbial peptide in potato, and can inhibit the growth of important phytopathogens. In this study, the transformation vector of SN1 gene expressing highly in monocot plants, pA25-SN1, was correctly constructed, in which SN1 gene was driven by maize ubiquitinpromoter. Four thousand embryo calli of Yangmai 18 were bombarded by the particle containing pA25-SN1. Among the regenerated 203 plants, 55 positive transgenic individuals were identified by PCR assay in the T₀ generation with a transformation frequency of 1.38%. The transgenic wheat plants from T₀ to T₂ generations were subjected to PCR, Southern blot, RT-PCR, and Q-RT-PCR assays. The disease responses of these positive transgenic plants were also evaluated by inoculating with Rhizoctonia cerealisand Bipolaris sorokiniana. The results showed that SN1 gene was integrated into these transgenic lines, inherited from T₀ to T₂, and expressed in the wheat background. The transgenic wheat plants expressing SN1 displayed anenhanced resistance to R. cerealis and B. sorokiniana compared with the untransformed Yangmai 18, and the enhanced resistance was inheritable.

Identification of Differential Expressed Proteins Responding to Phosphorus Starvation Based on Proteomic Analysis in Roots of Wheat (Triticum aestivum L.)

FENG Wan-Jun,LI Zhen-Xing,GUO Bao-Jian,PENG Hui-Ru,YAO Ying-Yin,NI Zhong-Fu,SUN Qi-Xin

Acta Agron Sin. 2012, 38(05):  780-790.  doi:10.3724/SP.J.1006.2012.00780

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Growth inhibition caused by phosphorus (P) deficiency is a serious problem for crop production. Plants can respond defensively to this stress by modifying their metabolic pathways and root morphologies through changes of quantity of low-Pi responding genes. To better understand the adaptation mechanisms of wheat to Pi deficiency conditions, a comparative proteome analysis was conducted in this study using wheat root samples treated 7 days without (–P) and with phosphorus (+P). Among 1 144 protein spots reproducibly detected, eighty seven of which (7.6%) were differentially expressed, including those present in treatments of only in –P or +P, and up- or down-regulated in –P. Moreover, 39 of the differentially expressed proteins were revealed to be involved in various biological processes such as metabolism, cell growth and division, transcription and translation, disease and defense, signal transduction, acting as transposable elements and unclassified proteins. Taken together, our results showed that wheat responds to the Pi starvation stress through an array of changes in metabolic states of cells and genes expression, which results in the maintenance of a relative P homeostasis in plants.

Quantification of Fusarium oxysporum f. sp. phaseoli Detected by Real-time Quantitative PCR in Different Common Beans Cultivars

XUE Ren-Feng,ZHU Zhen-Dong,HUANG Yan,WANG Xiao-Ming,WANG Lan-Fen,WANG Shu-Min

Acta Agron Sin. 2012, 38(05):  791-799.  doi:10.3724/SP.J.1006.2012.00791

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Fusarium wilt, caused by Fusarium oxysporum f. sp. phaseoli, is one of the most devastating vascular diseases of common bean. A efficient way to prevent and control the disease is to use resistant cultivars, so it is necessary to develop a rapid accurate method for detecting the pathogens. In this study, we developed a real-time quantitative polymerase chain reaction (qRT-PCR) protocol that quantified F. oxysporum f. sp. phaseoli DNA to a minimum of 1 pg in the plant roots and stems. Moreover, the qRT-PCR protocol asymptomatically distinguished resistant level of different bean cultivars challenged by the wilt pathogen FOP-DM01 at 6 d post inoculation. The result indicated FOP-DM01 DNA quantifications in the roots and stems of susceptible BRB-130 and A0640-1 were significantly higher than those in resistant 260205 and Heiyundou, which absolutely matched with the phenotypic identification. The use of this protocol for fast, reliable, and cost-effective quantification of F. oxysporum f. sp. phaseoli in asymptomatic tissues at early stages of the infection process is of great value for common bean breeding and studies of phytopathology and epidemiology.

Variation and Correlation Analysis of Hay Forage Quality Traits of Foxtail Millet (Setaria italica L.)

ZHI Hui,NIU Zhen-Gang,JIA Guan-Qing,CHAI Yang,LI Wei,WANG Yong-Fang,LI Hai-Quan,LU Ping,BAI Su-Lan,DIAO Xian-Min

Acta Agron Sin. 2012, 38(05):  800-807.  doi:10.3724/SP.J.1006.2012.00800

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Lack of information about hay forage quality of foxtail millet inbred lines has limited the development of foxtail millet as a forage crop. In this study, forty-seven foxtail millet landraces and improved cultivars were planted in north featured area of China for forage quality identification, frequency distributions of eight quality-related traits were characterized and outstanding lines were screened based on these results. For all the forty-seven accessions, rang of crude protein (CP) content was 5.42%–12.45%, with a CV of 14.25; rang of crude fat (CFa) content was 0.64%–1.43%, with a CV of 15.84; rang of crude ash (CA) content was 8.5%–15.6%, with a CV of 13.71; rang of total phosphorus (TP) content was 0.10%–0.32%, with a CV of 20; range of calcium (Ca) content was 0.27%–0.67%, with a CV of 20. Crude fiber (CF) content, nitrogen free extract (NFE) content and moisture (MC) content had a lower CV. According to our comprehensive analysis on these data, four lines Li05-569, Esilv, Xi295 and Honggengu were selected as the candidates for forage variety breeding of foxtail millet in the future

Cloning and Analysis on Full-length cDNA Sequence of Ubiquitin-conjugating Enzyme Gene from Oryza meyeriana Baill.

JIANG Chun-Miao,HUANG Xing-Qi,FU Jian,YU Teng-Qiong,ZHONG Qiao-Fang,LI Ding-Qin,YIN Fu-You,ZHANG Dun-Yu,WANG Ling-Xian,CHENG Zai-Quan

Acta Agron Sin. 2012, 38(05):  808-813.  doi:10.3724/SP.J.1006.2012.00808

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Based on the bioinformatic analysis of the ESTs from the subtraction cDNA library of Oryza meyeriana, we cloned one of the ESTs which has the homolog function of ubiquitin-conjugating enzyme and got a full-length cDNA sequence of ubiquitin-conjugating enzyme gene by RACE, and named it OmE2 (Oryza meyerianaBaill ubiquitin-conjugating enzyme, OmE2). This full-length cDNA sequence has 917 bp including 528 bp open reading frame encoding a protein of 175 amino acids, with a predicted molecular mass of 19.3 kD and pI of 9.32. OmE2 protein which had significant amino sequence identity and similarity with ubiquitin-conjugating enzyme from other species contained the conserved sequence and cysteine residue in active sites of ubiquitin-conjugating family. OmE2 had three trans-membrane domains. It is predicted that OmE2 protein is a kind of ubiquitin-conjugating protein and transmembrane protein. The expression of OmE2 inOryza meyeriana was induced by Xanthomonas campestris pv. oryzae. Therefore OmE2 gene which was first found in wild rice may participate in the signal transduction and the resistance response in Oryza meyeriana.

Effect of Successive Backcrossing on Eliminating Somaclonal Variation Caused by Agrobacterium-Mediated Transformation in Rice

YANG Zhou,CHEN Hao,TANG Wei,LIN Yong-Jun

Acta Agron Sin. 2012, 38(05):  814-819.  doi:10.3724/SP.J.1006.2012.00814

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Somaclonal variation caused by Agrobacterium-mediated transformation influences some agronomic traits of transgenic plants. As a result, a large number of T0 regenerated plants are required in the development of transgenic crop. Here, we successively backcrossed transgenic rice (Oryza sativa L.) to progenitor variety and evaluated agronomic performance of progeny, with the objective of eliminating somaclonal variation and recovering agronomic traits of transgenic parent. Three transgenic lines possessing different insect-resistance genes from Bacillus thuringiensis (Bt) were used as donor parents. They were backcrossed successively to the progenitor variety, and the individuals of each BC_nF₁ generation were then selfed twice, with selection for insect-resistance. BC_nF₃ homozygous lines, which were selected by a germination assay, caused an insect mortality of 100% in laboratory bioassay. In the field evaluation, these lines showed obviously higher yield than the donor parents and no significant differences from the progenitor variety in most agronomic traits. These results indicate that successive backcrossing can to a large extent recover agronomic traits of transgenic rice and reduce the workload required in transgenic breeding program.

Identification of QTLs for Glycinin (11S) and β-Conglycinin (7S) Fractions of Seed Storage Protein in Soybean by Association Mapping

JIAN Shuang,WEN Zi-Xiang,LI Hai-Chao,YUAN Dao-Hua,LI Jin-Ying,ZHANG Hui,YE Yong-Zhong,LU Wei-Guo

Acta Agron Sin. 2012, 38(05):  820-828.  doi:10.3724/SP.J.1006.2012.00820

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The glycinin (11S) and β-conglycinin (7S) are major components of seed storage protein in soybean, which play important roles in the functionality of seed protein. In the present study, association mapping was used to map the QTLs (quantitative trait loci) for glycinin (11S) and β-conglycinin (7S) fractions. One hundred and sixty-six accessions from Chinese soybean minicore collection were genotyped with 134 selected simple-sequence repeat (SSR) markers. The storage protein of each accession was separated by SDS-PAGE method, and gels were scanned for individual subunits of 11S and 7S by ImageQuant TL software. The association analysis between SSR loci and protein subunit components was performed with TASSEL GLM (general linear model) and MLM (mixed linear model) programs. The results showed that, both in 2008 and 2010, fourteen SSR loci associated with the protein subunit components were screened out by GLM program, and five SSR (Satt234, Satt595, Sat_062, Satt583, and Satt291) loci by MLM program, respectively. The high variation of 7S subunits was the main reason that caused 11S/7S ratio variance. Fewer loci were detected to be associated with the protein subunits whose phenotypic variations were higher, which might be due to the more recombination incidents during the evolution of the related genes. Therefore the LD decay distances of these genes were short, some QTLs could not be detected with limited SSR markers. The results of this study are meaningful for the marker assisted selection breeding of soybean varieties with higher protein quality.

Analysis on Genetic Diversity of Phenotypic Traits in Rice (Oryza sativa) Core Collection and Its Comprehensive Assessment

HU Biao-Lin,WAN Yong,LI Xia,LEI Jian-Guo,LUO Xiang-Dong,YAN Wen-Gui,XIE Jian-Kun

Acta Agron Sin. 2012, 38(05):  829-839.  doi:10.3724/SP.J.1006.2012.00829

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Germplasm resources are fundamental in rice breeding and dissecting complex traits; however, assessment of genetic diversity benefits the identification of optimal parental combinations to produce segregating offspring with maximum genetic variability, and facilitates the introgression of favorable genes from various germplasm into commercial cultivars. The USDA rice core collection (USDA-RCC) (1 579 rice accessions originated from six continents), was analyzed with 14 phenotypic traits to assess diversity and phenotypically superior rice germplasm. Themain results were summarized as follows: (1) Genetic distance of the germplasm from Asia and Africa to that of Oceania was larger. Rice germplasm from Asia, Africa and Oceania had accordingly greater phenotypic and genetic diversities, and genetic diversity of different traits was different among continents. Six traits including kernel length/width (KLW), alkali spreading value (ASC), plant height (PH), kernel width (KW), 1000-kernel weight (TKW) and amylose content (AC) had greater genetic diversity. (2) Comprehensive assessment of phenotypic traits was conducted using principal component analysis (392768 from Vietnam had the best comprehensive traits while the accession PI 281760 performed the worst comprehensive traits, and AC, HD, PH, lodging, BRC and HC would be suitable as comprehensive criteria for assessing USDA-RCC germplasm. We suggest these rice germplasm possessing great phenotypic diversity should be widely utilized in breeding programs, moreover, these rice germplasm with farther genetic distance and different comprehensive traits should be appropriately considered for the parental selection.PCA) and step regression analysis, demonstrating that the accession PI

Evaluation of Genetic Relationship in Ramie Based on RSAP, SRAP, and SSR

ZOU Zi-Zheng,CHEN Jian-Hua,LUAN Ming-Bao,GUO Jin-Xia,WANG Chao,WANG Xiao-Fei,XU Ying,SUN Zhi-Min

Acta Agron Sin. 2012, 38(05):  840-847.  doi:10.3724/SP.J.1006.2012.00840

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Ramie [Boehmeria nivea (L.) Gaud.] researches in molecular biology lags behind, there is a necessary to develop molecular markers in the genetic relationship analysis of ramie. In this paper, three molecular markers-RSAP, SRAP and SSR were used to cluster 16 Ramie germplasm. The result showed that each pair of primers could provide polymorphic sites and the site number was SRAP>RSAP>>SSR. Both results clustered based on SRAP and RSAP showed high consistency with that clustering based on combination of SRAP, RSAP and SSR, and the highly significant correlation coefficients were given. However, results of clustering based on SSR marker were quite different from the results based on combined markers. The rank order of similarities between the clustering results based on the molecular marker and phenotype was SRAP+RSAP+SSR>SRAP>RSAP>>SSR. For the study of genetic relationship among ramie germplasm, the efficiency of SRAP marker was slightly higher than that of RSAP marker, but that of SSR was low. Based on RSAP marker could efficiently display the polymorphism and genetic relationship among ramie varieties. Using the combined markers of RSAP&SRAP&SSR could be to reveal the genetic relationship of germplasm.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Relationship between Characteristics of Basal Internodes and Lodging and Its Physiological Mechanism in Dry-cultivated Rice

LIU Li-Jun,WANG Kang-Jun,Ge Li-Li,FAN Miao-Miao,ZHANG Zi-Chang,WANG Zhi-Qin,YANG Jian-Chang

Acta Agron Sin. 2012, 38(05):  848-856.  doi:10.3724/SP.J.1006.2012.00848

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Lodging is one of the most important factors restricting the wide extension of dry-cultivated rice (DCR). The objective of the study was to investigate the reasons for lodging in DCR using Shanyou 63 (indica hybrid combination) and 9516 (japonica) as materials. The results showed that the lodging percentage in DCR was significantly higher than that in conventional moist-cultivated rice (MCR), leading to significant decrease in seed-setting percentage and grain weight, and grain yield in DCR. The mechanical strength (thickness and weight per centimeter) and carbohydrate (especially starch) content in basal internodes from heading to maturity were much lower in DCR than in MCR, while α-amylase activity in basal internodes was higher in DCR than in MCR. The starch content was very significantly and positively correlated with thickness and weight per centimeter of basal internodes, and significantly or very significantly and negatively correlated with α-amylase activity in basal internodes. The starch exportation was significantly or very significantly and positively correlated with α-amylase activity. The application of silicon and potassium fertilizers could decrease α-amylase activity and increase the starch content in basal internodes, enhance the mechanical strength of basal internodes, decrease the lodging percentage, and increase seed-setting percentage and grain weight, result in the increase of grain yield in DCR. The results were reversed when 1/2 leaves were cut at booting stage. The results above indicated that the higher α-amylase activity in basal internodes in DCR caused more starch degradation, decreasing the mechanical strength of basal internodes, and resulting in the lodging in DCR.

Genotypic Responses and Physiological Mechanisms of Maize (Zea mays L.) to High Temperature Stress during Flowering

ZHAO Long-Fei,LI Chao-Hai,LIU Tian-Xue,WANG Xiu-Ping,SENG Shan-Shan,PAN Xu

Acta Agron Sin. 2012, 38(05):  857-864.  doi:10.3724/SP.J.1006.2012.00857

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Lodging is one of the most important factors restricting the wide extension of dry-cultivated rice (DCR). The objective of the study was to investigate the reasons for lodging in DCR using Shanyou 63 (indica hybrid combination) and 9516 (japonica) as materials. The results showed that the lodging percentage in DCR was significantly higher than that in conventional moist-cultivated rice (MCR), leading to significant decrease in seed-setting percentage and grain weight, and grain yield in DCR. The mechanical strength (thickness and weight per centimeter) and carbohydrate (especially starch) content in basal internodes from heading to maturity were much lower in DCR than in MCR, while α-amylase activity in basal internodes was higher in DCR than in MCR. The starch content was very significantly and positively correlated with thickness and weight per centimeter of basal internodes, and significantly or very significantly and negatively correlated with α-amylase activity in basal internodes. The starch exportation was significantly or very significantly and positively correlated with α-amylase activity. The application of silicon and potassium fertilizers could decrease α-amylase activity and increase the starch content in basal internodes, enhance the mechanical strength of basal internodes, decrease the lodging percentage, and increase seed-setting percentage and grain weight, result in the increase of grain yield in DCR. The results were reversed when 1/2 leaves were cut at booting stage. The results above indicated that the higher α-amylase activity in basal internodes in DCR caused more starch degradation, decreasing the mechanical strength of basal internodes, and resulting in the lodging in DCR.

Accumulation and Distribution of Hydrogen Peroxide in Interaction between Sugarbeet Plant and Sugarbeet Necrotic Yellow Vein Virus

CHEN Yu-Zhen,ZHANG Shao-Ying,KANG Zhen-Sheng,HAN Qing-Mei,BAI Zhen-Qing

Acta Agron Sin. 2012, 38(05):  865-870.  doi:10.3724/SP.J.1006.2012.00865

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Hydrogen peroxide (H₂O₂) plays an important role in the interaction between plant and pathogen defense response. The objective of thisresearch was owing the interaction system of beet necrotic yellow vein virus (BNYVV) and resistant, susceptible sugarbeet lines to disclose the relationship of accumulation and distribution of H₂O₂ with sugarbeet rhizomania resistance. The production and accumulation of H₂O₂ in the two interaction systems were detected and the distribution of H₂O₂ was observed in subcellular level using the cytochemical technique. The result showed that there was plenty of H₂O₂ in both interaction systems, and the production of H₂O₂ was evidently higher in the resistant lines than with in the susceptible lines. In addition, distribution and the location of H₂O₂ were similar in the two lines, where we observed mainly in the tonoplast and the plasma membrane of host root, vein cells as well as the intercellular space of some host vein cells. But there were obvious differences in the content of H₂O₂ accumulated in the two interaction lines, the deposition of H₂O₂ in the susceptible line was significantly lower than that in the resistant line, showing it may have a close relationship with resistance of sugarbeet against rhizomania, H₂O₂ showed the involved in the defense responses to virus infection in sugar beets.

Photosynthesis and Chloroplast Ultra-structure Characteristics of Flag Leaves for a Premature Senescence Rice Mutant

WANG Fu-Biao,HUANG Fu-Deng,CHENG Fang-Min,LI Zhao-Wei,HU Dong-Wei,PAN Gang,MAO Yu-Chan

Acta Agron Sin. 2012, 38(05):  871-879.  doi:10.3724/SP.J.1006.2012.00871

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The influences of leaf premature senescence at the filling stage on photosynthesis rate, chlorophyll fluorescence and chloroplast ultra-structure were investigated using Zhehui 7954 (an excellent indica restorer line) and its leaf senescence mutant (psf). The results indicated that the psf mutant had significantly negative influence on the numbers of filling grains per panicle, seed-setting rate, 1000-grain weight and yield per plant, especially on the numbers of filling grains per panicle and seed-setting rate. Compared with CK, psf also exhibited dramatically lower chlorophyll content, the ratio of chlorophyll a/b, photosynthetic rate (P_n) and chlorophyll fluorescence parameters F_v/F_o and F_v/F_m at filling stage, which were further lowered in the process of maturity. No visual changesin the ultra-structure of mesophyll cells and chloroplasts were observed for psf, showing its intact thylakoid, plastoglobuli size and shape. However, abnormal shape and stacking parallel distribution of chloroplasts, near the cell wall, the degraded grana, the plastoglobuli residue and the destroyed chloroplast membrane could be detected in psf mesophyll cells, in which the appearance of stacking and spherical chloroplasts was responsible for the dropped P_n in psf leaf prior to the degradation and disintegration of thylakoid and grana membrane, thereby caused the decrease of F_v/F_o and F_v/F_m.

Effects of Root Border Cells on Root Growth and Cell Wall Polysaccharide Contents in Rice Seedlings and Their Relation to Aluminum Tolerance

XING Cheng-Hua,ZHANG Shu-Na,WU Kun,WANG Ning,LING Yun

Acta Agron Sin. 2012, 38(05):  880-886.  doi:10.3724/SP.J.1006.2012.00880

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Most plant root tips are sheathed by large populations of root border cells (RBCs). One of suggested roles of RBCs is to defend from toxic metal cations, including Al, in the rhizosphere. Using rice genotypes “II You 3027” (Al-resistant) and “Hongliangyou 166” (Al-sensitive) with treatments of different concentrations of Al³⁺, acroponic culture with RBCs adhered to or removed from root tips was conducted to study the effects of RBCs on root growth, Al content and cell wall polysaccharide contents in root tips of rice seedlings under Al toxicity. Al treatment inhibited root elongation and increased Al accumulation in the root tips. Removal of RBCs from root tips significantly enhanced Al-induced root growth inhibition and increased callose content, Al accumulation in root tips and root tip cell walls, and monomeric Al content in root tips. The removal of RBCs from root tips also significantly increased pectin and hemicellulose 1 contents in the cell walls of root tips, but did not affect the hemicellulose 2 contents. These results suggested that RBCs adhered to the root tips enhance Al tolerance of rice by decreasing Al, pectin and hemicellulose 1 contents in the cell walls of root tips, and contents of toxic species of Al in root tips.

Differences of Nitrogen Status between Different N-uptake-efficiency Rapeseed (Brassica napus L.) Cultivars

CAO Lan-Qin,WU Xiao-Ming,YANG Rui,TIAN Yang-Yang,CHEN Xian-Ni,CHEN Bi-Yun,LI Ya-Jun,GAO Ya-Jun

Acta Agron Sin. 2012, 38(05):  887-895.  doi:10.3724/SP.J.1006.2012.00887

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A pot experiment was conducted to test nitrogen (N) uptake efficiency (NUE) of 50 rapeseed cultivars at two N application levels. The differences of N status indexes between high-nitrogen-efficiency-genotype (HNEG) and low-nitrogen-efficiency-genotype (LNEG) were analyzed. The results showed that N status varied dramatically among different genotypes. The greatest variance was found on N accumulation in root and ratio of N accumulation in root to total N uptake (>50%) while the least variance was found on N content of aboveground part of rapeseed during vegetative stage. At two N application levels, HNEG had significantly greater total N uptake and N accumulation in different parts of plant than LNEG. The maximum difference of N accumulation was found in root between HNEG and LNEG while the minimum difference of N accumulation was found in silique. The ratioof N accumulation in root to total N uptake for HNEG was higher than that for LNEG. The ratio of N accumulation in silique to total N uptake was higher for LNEG than for HNEG. During vegetative stage, no significant difference of N content of aboveground parts was found between HNEG and LNEG. However, HNEG had remarkable higher N accumulation in aboveground parts and higher SPAD value of leaves than LNEG. Changes of N supply level led to the greater changes of N content, N accumulation and the ratio of N accumulation in any part to total N uptake for HNEG than those for LNEG. Significant differences of nitrogen status between different rapeseed cultivars provide a basis to create new crop varieties for increase nitrogen use efficiency.

Change of Rice Yield Gaps and Influential Climatic Factors in Southern China

SHI Quan-Hong,LIU Jian-Gang,WANG Zhao-Hua,TAO Ting-Ting,CHEN Fu,CHU Qing-Quan

Acta Agron Sin. 2012, 38(05):  896-903.  doi:10.3724/SP.J.1006.2012.00896

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In order to study theoretical potential productivity, yield promotion space, yield constraints and the solution approaches,we used AEZ (Agricultural Ecology Zone) model to estimate the photothermal potential productivity of rice and calculate the rice yield gaps from 1980 to 2010 in southern China. The results showed that early rice potential productivity continued to increase with grater increasing rate than the actual yield, so the early rice yield gap became bigger. The potential productivity of medium rice and late rice was declined; and the rice yield gap became smaller. The analysis of climatic factors showed that temperature and radiation in rice growth period were the most important impact factors for rice potential yield and yield gaps. The positive effect of temperature increasing for the early rice was bigger than the negative effect of radiation declining, resulting in the increase of the potential productivity. On the contrary, the negative effect of radiation declining for medium rice and late rice was bigger, so the potential productivity was dropping. The temperature and radiation in rice growth period were different, causing different changing trends of rice potential yield and yield gap between provinces.

RESEARCH NOTES

Functions of OsBTF3 Gene in Regulation of Photosynthesis, Growth and Development in Rice

LI Guang-Xu,CHEN Hua-Min,WU Mao-Sen,HE Chen-Yang

Acta Agron Sin. 2012, 38(05):  904-908.  doi:10.3724/SP.J.1006.2012.00904

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To reveal the regulatory roles of transcription factor OsBTF3 in growth and development of rice, we comparably analyzed the growth and development of the transgenic rice with over-expressed or RNAi-silenced OsBTF3 gene. Results showed that significant increases in chlorophyll content, chloroplast number, photosynthetic rate, leaf size, plant heights and stem internode length were found in T₁ generation of transgenic rice lines with the over-expressed gene compared to wild-type control plants, while remarkable decreases in above phenotypes were observed in plants with the RNAi-silenced gene. Over-expression or silencing of transgene OsBTF3 in rice resulted in significant changes in photosynthesis, growth and development of rice. Therefore, OsBTF3 functions as a key regulator in growth and development, and might be potentially used in molecular breeding of rice for improving agronomic traits.

Study on Salt Tolerance of Wheat in Hetao Irrigation District and Its Ecological Adaptable Region

TONG Wen-Jie,LIU Qian,CHEN Fu,WEN Xin-Ya,LI Zhong-Hao,GAO Hong-Yong

Acta Agron Sin. 2012, 38(05):  909-913.  doi:10.3724/SP.J.1006.2012.00909

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Using the major local wheat cultivar Yongliang 4, the effect of salinity in different soil layers on yield and its components of wheat was investigated in 20 farmers' fields in Hetao Irrigation District which was in Inner Mongolia, China. And salt tolerance of wheat and its ecological adaptable region were studied in this district. The results showed that ECe of 0 to 10 cm soil layer at wheat seedling stage was the most representative as the root-zone salinity index to analysis wheat salt tolerance, the salt tolerance index of wheat was 10.465 for this soil layer. There were significant negative correlations between soil salinity and wheat yield components, especially between soil salinity and spike number per hectare. According to the wheat salt tolerance, and the wheat relative yield reduction of ≤10%, 10–25%, 25–50%, and ≥50% as the division standard, we divided the farm land into the most suitable region, suitable region, sub-suitable region and unsuitable region, where the electrical conductivities of saturation extract of the 0-10 cm soil at wheat seedling stage were ≤4.972, 4.972–6.747, 6.747–9.196, and ≥9.196 dS m^-1, respectively.

Identification and Genetic Analysis of Hybrid from Cross between Erianthus arundinacius (Retz.) Jesws. and Saccharum spontaneum L.

LIU Xi-Hui,FANG Feng-Xue,GAO Yi-Jing,ZHANG Rong-Hua,SONG Huan-Zhong,YANG Rong-Zhong,FANG Wei-Kuan,DUAN Wei-Xing,LUO Ting, ZHANG Ge-Min,LI Yang-Rui

Acta Agron Sin. 2012, 38(05):  914-920.  doi:10.3724/SP.J.1006.2012.00914

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Hybridization between different populations is the most common means to enrich genetic variation. Studies on genetic differentiation and characterizations of hybrid are crucial to protect and evaluate genetic resources. In this paper, the hybrid from Erianthus arundinacius (Retz.)Jesws. × Saccharum spontaneum L. were analyzed using SSR and SRAP markers. The results showed that the hybrid GXAS07-6-1 was the true hybrid identified by using three pairs of SSR primers and five pairs of SRAP primers. A total of 1 095 DNA bands were amplified by 71 pairs of selective SRAP primers. Among 1 095 genetic loci, 800 were polymorphic. Therefore, the average polymorphic ratio was 73.0% and each pair of SRAP primers yielded 11 polymorphic loci on average. The genetic relationship between the hybrid and its parents analyzed with software NTSYS-pc2.10e showed that the genetic similarity coefficient was 0.474 between the parents, while 0.696 between the hybrid and the female parent and 0.752 between the hybrid and the male parent, suggesting that the hybrid GXAS07-6-1 was more inherited from male parent.

Optimization of Two-dimensional Electrophoresis Condition for Rice Grain Protein and Comparison of Relevant Proteomic Methods

LI Qi-Song,CHEN Jun,LIN Shi-Sheng,LI Zhong,ZHANG Zhi-Xing,LIN Wen-Xiong

Acta Agron Sin. 2012, 38(05):  921-927.  doi:10.3724/SP.J.1006.2012.00921

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A suitable proteomic strategy for rice grain protein research is important for further understanding rice grain development at proteome level. In this study, three different protein extraction methods were compared and then electrophoretic conditions of hand-made gel lands and IPG lands in IEF (isoelectric focusing) were optimized. Furthermore, three important proteomic research strategies (MALDI-TOF/MS, western-blot and phosphoproteome) were used for identification and analysis of in-gel proteins. The results showed that the method of soluble protein extraction was most suitable for investigation of grain proteomics, with a well-distributed 2-DE gel profile under optimized electrophoretic conditions, and it was confirmed that MALDI-TOF/MS, western-blot and phosphoproteome were the three suitable methods for the analysis of in-gel proteins. The establishment of the suitable system for rice grain proteomic research paves the way for the next step to further analyse rice grain development at proteome level.

Association of Kernel Hardness and Puroindoline Genes with Alveograph and Mixolab Parameters

CHEN Feng,LI Huan-Huan,ZHANG Fu-Yan,SHANG Xiao-Li,XU Hai-Xia,CUI Dang-Qun

Acta Agron Sin. 2012, 38(05):  928-933.  doi:10.3724/SP.J.1006.2012.00928

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A total of 35 wheat advanced lines with three replications from the Yellow and Huai Valley wheat region of China were identified for SKCS (single kernel characterization system) hardness index and puroindoline alleles as well as parameters of Alveograph and Mixolab. The results indicated that SKCS hardness index possessed highly significant correlations (P < 0.01) with Mixolab parameters of C1, C2, C3, C4, range of torque, water absorption, and C3-C2 and Alveograph parameters of P, L, G, and P/L. Most of the Alveograph and Mixolab parameters were significantly affected (P < 0.01) by puroindoline genes. For Alveograph parameters, the averages of P, W, and P/L were significantly higher (P < 0.05) in the Pina-D1b lines than in the wild type and the Pinb-D1b lines, but the averages of L, G, and Ie were significantly higher (P < 0.05) in the wild type than in both Pina-D1b and Pinb-D1b lines. For Mixolab parameters, the averages of C1, C2, C2-C1, range of torque, and water absorption were significantly higher (P < 0.05) in both Pinb-D1b and Pina-D1b lines than in the wild type, whereas the averages of C3, C4, and C5 were significantly higher (P < 0.05) in the wild type than in the Pinb-D1b and Pina-D1b lines.