接种根瘤菌环境下大豆叶形遗传及QTL定位分析

为探究接种根瘤菌环境下影响大豆叶形的遗传基础,本研究利用两个叶形具有显著差异的大豆品种及RIL群体,在接种和不接种根瘤菌环境下对大豆叶形性状进行遗传和QTL定位等分析。结果显示,叶形相关性状的遗传率在0.60~0.95之间,环境与基因型间存在互作效应,并且接种根瘤菌可以显著影响叶形指数（LS）与单株粒数（GN）、单株荚数（PD）和单株粒重（GW）的相关系数。此外,两种处理下共检测到8个QTL位点,LOD值范围在2.50~7.03,可解释6.4%~16.9%的遗传变异。其中,qLS-15可解释由根瘤菌×基因型互作引起叶形性状6.4%~9.3%的遗传变异,LOD值在2.50~3.69之间,表明qLS-15是与环境互作的主要遗传位点之一。综上所述,根瘤菌可以通过qLS-15影响大豆叶形,研究结果为解析根瘤菌提升大豆产量的内在机制提供了理论依据。     

利用高世代回交群体对大豆小粒性状的基因型分析及QTL定位

利用野生型大豆ZYD00006（供体亲本）与主栽品种绥农14（轮回亲本）所构建的高世代回交导入系,经过严格的百粒重筛选鉴定,得到43个百粒重性状明显小于轮回亲本的导入系个体。利用这套选择群体结合随机对照群体和基因型分析,通过基于遗传搭车原理的卡方分析,检测到分布于7个连锁群上的9个与大豆小粒性状相关的QTL位点,对小粒性状表现为正效应,为大豆小粒性状分子辅助育种提供有用的分子标记。     

QTL mapping of grain quality traits in rice

Grain quality improvement is one of the most important goals in a rice breeding program. An indica variety with small grain size was crossed to a japonica variety with large grain size to construct a set of recombinant inbred lines (RILs) which was used to identify quantitative trait loci (QTLs) controlling eight grain quality traits. Based on a linkage map of 185 SSR markers, a total of 16 QTLs were mapped on six chromosomes. A pleiotropic main effect QTL (M-QTL) flanked by RM3204 and RM16 on chromosome 3 influences the grain length (GL), length width ratio (LWR) and head rice ratio (HRR), explaining the phenotypic variation of 46.0, 36.1 and 29.7%, respectively. A total of 18 epistatic QTLs were identified for all the traits except MRR, distributed on all the chromosomes except chromosome 10. Two M-QTLs for GL and one M-QTL for GW were involved in epistatic QTL. No significant interaction between M-QTL or epistatic QTL and environment was detected except AC having significant M-QTL by environment interaction with minor effect. GL and LWR have a significant negative relation with HRR which might make it difficult to develop long grain with higher HRR in the rice breeding practice.     

西藏半野生小麦粒型性状的QTL定位

为了解西藏半野生小麦粒型性状的QTL差异,以西藏半野生小麦Q1028和郑麦9023(ZM9023)杂交后获得的重组自交系群体为试验材料,于2012、2013和2015年分别在四川农业大学温江试验田种植,对其粒型性状(粒长、粒宽、粒厚、长宽比、籽粒大小)进行遗传分析。结果表明,重组自交系群体粒型性状均呈正态分布,对籽粒大小的影响依次为粒宽、粒厚、粒长。在三个年度环境中,总共检测到33个控制小麦粒长、粒宽、粒厚、籽粒大小和长宽比的QTL位点。其中,13个控制粒长的QTL分布在1B、2B、2D(3个)、3A、4A、5B、6A、6B、7A(3个)染色体上,每个位点对表型变异的贡献率为5.37%~11.57%。6个控制粒宽的QTL分布在2B、2D、4A、5B、6A、7A染色体上,可以解释表型变异的6.43%~12.69%。3个控制粒厚的QTL位于2B和2D(2个)上,表型贡献率分别为12.75%、10.00%和8.49%。9个控制籽粒大小的QTL分别位于2B、2D(2个)、4A、5B、6A、7A(3个)染色体上,单个QTL可解释6.26%~14.69%的表型变异。另外,本研究还在2B、2D、4A、5B、6A、7A染色体上共发现7个QTL富集区,这些染色体上的QTL和富集区与籽粒性状密切相关,在育种中值得关注。其中,2B染色体上XwPt-3561~XwPt-6932分子标记区间内有控制粒长、粒宽、粒厚、籽粒大小的遗传位点,6A染色体上标记wpt-730109与wpt-7063之间有控制增加籽粒宽度和籽粒大小的位点。     

Kernel morphometric traits in hexaploid wheat (Triticum aestivum L.) are modulated by intricate QTL × QTL and genotype × environment interactions

Wheat kernel size and shape influence its flour yield and market price. A hexaploid wheat population of 185 recombinant inbred lines was evaluated for five kernel morphometric traits namely, 1000-kernel weight, kernel length, width, length–width ratio and factor form density in two diverse agro-climatic regions in India in five to eight year–location combinations. Additive main effects and multiplicative interaction analysis revealed significant contributions from genotype (G) and genotype × environment (G × E) effects for these traits. Quantitative trait locus (QTL) analysis by composite interval mapping (CIM) was performed using a linkage map of 251 SSR markers and 59 QTLs distributed on 16 chromosomes were identified. The majority of the QTLs were located on the D genome (44.07%) and the homeologous chromosomes of Group 2 (38.98%). Stable QTLs detected in three or more year–location combinations were identified for four traits. Multi-trait CIM showed 10 chromosomal regions harboring putative pleiotropic loci. Complexity in the genetic effects was further revealed by QTL analysis based on mixed-linear model that indicated 19 QTLs with significant individual effects (main-effect QTLs) and 14 QTL × QTL interactions. Five of these nineteen main-effect QTLs and one of the fourteen QTL × QTL interactions showed environmental influence.     

Silencing of puroindoline a alters the kernel texture in transgenic bread wheat

Grain hardness is an important end-use quality parameter of bread wheat, and one of the most important characters for quality improvement. The objective of this study was to further understand the function of puroindolines and the underlying mechanism in the formation of kernel texture. The highly efficient expression vector pUBPa harboring puroindoline a (Pina) was introduced into the bread wheat cultivar Zhongyou 9507-60 via biolistic transformation and transgenic plants were obtained. The integration of the foreign Pina gene was confirmed by PCR and genomic DNA Southern blot analysis. The levels of friabilin on the surface of water-washed starch granules varied among the transgenic lines. SDS-PAGE analysis of Triton X-114 extracted protein showed that the PINA protein was absent in three transgenic lines, indicating that the endogenous Pina gene most likely had been co-suppressed by the over-expression of the Pina transgene. SKCS kernel hardness and scanning electron microscopy analysis further confirmed the changes of kernel texture in these lines.     

Effect of heat stress on wheat proteins during kernel development in wheat near-isogenic lines differing at Glu-D1

Two near-isogenic lines of the wheat variety Lance having Glu-D1a (HMW-GS 2 + 12) and Glu-D1d (HMW-GS 5 + 10) were subjected to several regimes of heat stress. In 2001, the temperature regimes were (i) 20/16 (day/night, °C) from planting to maturity, (ii) 20/16 except for a 3-day heat treatment of 35/20, 25 days after anthesis and (iii) 20/16 until 25 DAA, after which plants were subjected to 40/25 until maturity. In 2002, treatments (i) and (iii) were the same while treatment (ii) used a temperature of 40/25 °C for 3 days at 25 DAA. Seed was collected at 3-day intervals starting from 16 days after anthesis and analyzed for protein composition by SE-HPLC. The line with the Glu-D1d allele showed an earlier polymerization of glutenin than its allelic counterpart and a higher molecular weight of glutenin at maturity, this being deduced from measurements of the percentage of unextractable polymeric protein. It is postulated that the timing and rate of glutenin polymerization, and the timing of high temperature application may be the key factors contributing to an explanation of the effect of heat stress on functionality.     

玉米自交系子粒大小和形状分类及其与营养成分相关分析

使用包含丰富遗传变异的508份玉米自交系对玉米子粒大小和形状等8个性状进行考察,分析其在不同遗传材料间的分布差异,基于该群体建立子粒大小的分类指标,研究子粒大小和形状与子粒营养间的相关性。结果表明,子粒大小和形状等8个性状的平均变异系数(CV)为10.8%,其中,粒长变异大于粒厚和粒宽;粒厚和粒宽呈高度正相关,粒厚和粒长呈较强负相关,同时粒长和粒宽相关不显著;子粒整体大小在不同类群中的变异较小,粒长、粒厚、粒宽长比等形状性状在不同类群中差异显著,其中,坚秆综合群材料的子粒偏长、偏薄,热带/亚热带及非坚秆综合群材料的子粒偏宽、偏厚。508份自交系被分为特大粒、大粒、中粒、小粒和特小粒5个类别,子粒大小和形状等8个性状和子粒营养的相关性都较弱,且大部分为负相关,表明子粒大小和形状不是决定子粒营养的主要因素。     

Flanking SSR markers for alleles involved in the necrosis of hybrids between hexaploid bread wheat and synthetic hexaploid wheat

Hybrid necrosis in wheat (Triticum aestivum L.) is the premature death of leaves or plants caused by the interaction of two dominant complementary genes, Ne1 and Ne2, located on chromosomes 5B and 2B, respectively. We examined allelic interaction effects of necrosis alleles using simple sequence repeat (SSR) markers in F₂ populations derived from crossing the cultivar “Alsen” with a synthetic hexaploid “TA4152-37”. The SSR marker Xbarc7 was linked at a distance of 3 cM to the quantitative trait loci (QTL) located on chromosome 2B, and Xgwm639 was 11 cM from the 5B QTL. A significant additive by additive epistatic interaction was detected between Ne1 and Ne2 QTL, and the results suggest that Alsen possesses a moderate necrosis allele, Ne2^m; whereas, TA4152-37 possesses a moderate necrosis allele, Ne1^m. The Ne2^m allele had a stronger effect than the Ne1^m allele, and a total of 94.6% of phenotypic variance was explained by these genes and their interactions. This demonstrates the strong phenotypic effect due to even moderate necrosis alleles, and emphasizes the need for breeders to accurately predict and identify hybrids that will result in necrosis.     

Genome-wide association mapping of starch granule size distribution in common wheat

Starch is a crucial component in wheat endosperm and plays an important role in processing quality. Endosperm of matured wheat grains contains two distinct starch granules (SG), referred to as larger A- and smaller B-granules. In the present study, 166 Chinese bread wheat cultivars planted in four environments were characterized for variation in SG size. A genome-wide association study (GWAS) using the 90 K SNP assay identified 23 loci for percentage volumes of A- and B-granules, and 25 loci for the ratio of A-/B-granules volumes, distributing on 15 chromosomes. Fifteen MTAs were associated with both the percentage volumes of A-, B-granules and the ratio of A-/B-granules volumes. MTAs IWB34623 and IWA3693 on chromosome 7A and IWB22624 and IWA4574 on chromosome 7B associated with the percentage volumes of A- and B-granules consistently identified in multiple environments were considered to be stable. Linear regression analysis showed a significantly negative correlation of the number of favorable alleles with the percentage volumes of A-granules and a significantly positive correlation between the number of favorable alleles and the percentage volumes of B-granules, respectively. The loci identified in this study and associated markers could provide basis for manipulating SG size to obtain superior noodle quality in wheat.     

Nutrient composition of groundnut cultures (Arachis hypogaea L.) in relation to their kernel size

Seven varieties of groundnuts of varying kernel size were selected to study the relation between kernel size and nutritional quality. Results indicated that no significant (r=0.22) difference was found in oil contents among the various varieties which ranged from 46–52 percent. Protein contents ranged from 17–25.2 percent. Protein content of small seed varieties was high compared to bold seeded varieties, whereas sugar content of bold seeded varieties was higher. No significant differences in amino acid and fatty acid compositions were observed among the varieties tested. In vitro digestibility of protein tended to be slightly less but not significantly so in bold seeded varieties compared to small and medium size varieties. Niacin content of bold seeded varieties was slightly higher compared to other varieties.     

Identification of novel secaloindoline-a and secaloindoline-b alleles in CIMMYT hexaploid triticale lines

To characterize kernel hardness, an important trait in triticale breeding, and to identify secaloindoline alleles present in hexaploid triticale lines developed at International Maize and Wheat Improvement Center (CIMMYT) a total of 171 secondary hexaploid lines were analyzed for grain hardness using the Single Kernel Characterization System. They showed a large spectrum of kernel hardness types, from very soft to very hard, with values ranging from 8.6 to 84.9. The occurrence of starch granule-associated friabilin was studied in 30 lines, including 10 hard, 9 mixed and 11 soft genotypes. All soft lines displayed a high level of friabilin, whereas the hard lines showed almost no friabilin, indicating that friabilin is directly involved in the formation of grain texture in secondary hexaploid triticales. Two novel secaloindoline alleles were identified and designated as Sina-R1b and Sinb-R1c. Compared with SINAa, the deduced amino acid sequence of SINAb showed a Trp to Arg substitution at position 44. SINBc had a Gly to Ser substitution at position 78 and a Gly to Arg substitution at position 115, as well as a Cys insertion in the signal peptide, in comparison to SINBa. The novel alleles Sina-R1b and Sinb-R1c were detected in both the soft and hard triticale lines.     

QTL mapping of agronomic and economic traits for four F2 populations of upland cotton

Background:Upland cotton(Gossypium hirsutum)accounts for more than 90%of the annual world cotton output because of its high yield potential.However,yield and fiber quality traits often show negative correlations.We constructed four F₂populations of upland cotton,using two normal lines(4133B and SGK9708)with high yield potential but moderate fiber quality and two introgression lines(Suyuan04–3 and J02–247)with superior fiber quality,and used them to investigate the genetic basis underlying complex traits such as yield and fiber quality in upland cotton.We also phenotyped eight agronomic and economic traits and mapped quantitative trait loci(QTLs).Results:Extensive phenotype variations and transgressive segregation were found across the segregation populations.We constructed four genetic maps of 585.97 centiMorgan(cM),752.45 cM,752.45 cM,and 1163.66 cM,one for each of the four F₂populations.Fifty QTLs were identified across the four populations(7 for plant height,27 for fiber quality and 16 for yield).The same QTLs were identified in different populations,including qBW4 and qBW2,which were linked to a common simple sequence repeat(SSR)marker,NAU1255.A QTL cluster containing eight QTLs for six different traits was characterized on linkage group 9 of the 4133B×Suyuan04–3 population.Conclusions:These findings will provide insights into the genetic basis of simultaneous improvement of yield and fiber quality in upland cotton breeding.     

Variation in kernel characteristics and protein molecular weight distribution of Langdon durum-wild emmer wheat chromosome substitution lines

Triticum turgidum L. var. dicoccoides (DIC) provides a useful source of genes to improve agronomic and quality characteristics of durum wheat. Research was performed to identify DIC chromosomes that carry useful genes for quality improvement. Langdon-T. dicoccoides substitution lines consisting of 13 lines based on DIC accession PI 481521, 10 lines on PI 478742, and 2 lines on Israel A were evaluated for kernel characteristics and protein molecular weight distribution. DIC chromosomes 3A from PI 481521, and 1A and 7A from PI 478742 increased kernel hardness. Chromosome 2A from PI 481521 increased kernel weight, which resulted in increased semolina yield. Some substituted DIC chromosomes also affected grain protein concentration and protein molecular weight distribution. For example, chromosomes 2A, 5B, and 7B from PI 481521, and 6B from Israel A increased total protein concentration, which was primarily attributed to an increase of SDS soluble gliadins. Chromosome 6B from PI 478742 was unique in that it led to an increase in SDS insoluble high molecular weight polymeric proteins, which contributed to increased dough mixing strength. Results from this research indicated that chromosome 6B from PI 478742 is a potential gene source to improve dough characteristics of durum wheat by increasing insoluble high molecular weight polymeric protein concentration.     

花生荚果大小和重量相关性状的QTL定位分析

荚果相关性状是花生产量构成的重要成分。为解析花生产量及产量相关性状的遗传基础,挖掘稳定存在的QTL,以荚果大小和重量存在显著差异的中花5号和ICGV 86699为亲本衍生的包含166个重组自交系群体为材料,对3个荚果相关性状中荚果长、荚果宽在5个环境,百果重在6个环境下进行性状考察,并结合群体的基因分型数据进行QTL定位分析。共检测到9个荚果长QTL、10个荚果宽QTL和12个百果重QTL。有10个QTL在多个环境被重复检测到,其中6个QTL在不同地点重复检测到,为稳定表达QTL,且稳定表达的QTL中5个（qPLB06.2、 qPLB06.3、qPWB06.2、qHPWB04.3、qHPWB06.3）在至少1个环境中贡献率超过10%。共发现5个QTL簇,其中位于 B06上的QTL簇Ⅳ和Ⅴ,均在多个环境下检测到稳定调控荚果长、荚果宽和百果重的QTL共定位,表明这些荚果相关性状具有明显的遗传相关性。      

Combined linkage and association mapping reveals two major QTL for stripe rust adult plant resistance in Shaanmai 155 and their haplotype variation in common wheat germplasm

The development and deployment of diverse resistance sources in new wheat cultivars underpin the durable control of stripe rust. In the present study, two loci for adult plant resistance(APR),QYr SM155.1 and QYr SM155.2, were identified in the Chinese wheat breeding line Shaanmai 155.QYr SM155.1 was mapped to a 3.0-c M interval between the single-nucleotide polymorphism(SNP) markers AX-109583610 and AX-110907562 on chromosome arm 2 BL. QYr SM155.2 was mapped to a 2.1-c M interval flanked by the ...     

Proteomic analysis of the mature kernel aleurone layer in common and durum wheat

The aleurone layer (AL) is one of inner tissues removed from the grain with the wheat bran. It is the main source of vitamins, minerals and antioxidants of potential nutritional value in the wheat kernel. The AL of three varieties of each of the two main species of wheat, Triticum aestivum (ABD) and Triticum durum (AB), were manually dissected and analysed using two-dimensional gel-based proteomics. A total of 1258 and 1109 Coomassie-stained spots were detected in the AL of representatives of the ABD and AB genomes. In two varieties (T. aestivum Chinese Spring and T. durum Bidi17), grown in two different years with full fungicide protection, no quantitative or qualitative (presence/absence) differences in spots were detected, suggesting that AL proteome is strongly genetically controlled. Comparison within and between species revealed a total of 339 AL significant protein spots. Among these spots, 30.8% differed within T. aestivum and 56.5% within T. durum varieties, whereas only 12.7% differed between the two species. Among the 142 AL proteins identified using MALDI-TOF and LC-MS/MS, 57% were globulin type storage proteins (Glo-3, Glo-3B, Glo-3C, Glo-2), 16.2% were involved in carbohydrate metabolism and 17.6% in defence/stress pathways. These variations in AL proteome are discussed.