International Maize and Wheat Improvement Center China Office

Beijing, China

International Maize and Wheat Improvement Center China Office

Beijing, China
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Wang L.,Chinese Academy of Agricultural Sciences | Li G.,Shandong Academy of Agricultural Sciences | Pena R.J.,International Maize and Wheat Improvement Center | Xia X.,Chinese Academy of Agricultural Sciences | And 2 more authors.
Journal of Cereal Science | Year: 2010

Low-molecular-weight glutenin subunits (LMW-GS) play a key role in determining the processing quality of the end-use products of common wheat. The objectives of this study were to identify genes at Glu-A3 locus, develop the STS markers, and establish multiplex PCR with the STS markers for Glu-A3 alleles. Gene-specific PCR primers were designed to amplify six near-isogenic lines (NILs) and Glenlea with different Glu-A3 alleles (a, b, c, d, e, f and g) defined by the protein electrophoretic mobility. Three Glu-A3 genes with complete coding sequence were cloned, designated as GluA3-1, GluA3-2 and GluA3-3, respectively. Seven dominant allele-specific STS (sequence tagged sites) markers were designed based on the SNPs (single nucleotide polymorphisms) among different allelic variants for the discrimination of the Glu-A3 protein alleles a, b, c, d, e, f and g. Four multiplex PCRs were established including Glu-A3b + Glu-A3f, Glu-A3d + Glu-A3f, Glu-A3d + Glu-A3g, and Glu-A3b + Glu-A3e. These markers and multiplex-PCR systems were validated on 141 CIMMYT wheat varieties and advanced lines with different Glu-A3 alleles, confirming that they can be efficiently used in marker-assisted breeding. © 2010 Elsevier Ltd. All rights reserved.

Rasheed A.,Chinese Academy of Agricultural Sciences | Rasheed A.,Quaid-i-Azam University | Xia X.,Chinese Academy of Agricultural Sciences | Yan Y.,Capital Normal University | And 4 more authors.
Journal of Cereal Science | Year: 2014

Wheat seed storage proteins, especially glutenins and gliadins, have unique functional properties giving rise to a wide array of food products for human consumption. The wheat seed storage proteins, however, are also the most common cause of food-related allergies and intolerances, and it has become crucially important to understand their composition, variation and functional properties and interface this knowledge with the grain handling industry as well as the breeders. This review focuses on advances in understanding the genetics and function of storage proteins and their application in wheat breeding programs. These include: (1) The development and validation of high-throughput molecular marker systems for defining the composition and variation of low molecular weight glutenin subunits (LMW-GS) genes and a summary of the more than 30 gene-specific markers for rapid screening in wheat breeding programs; (2) The identification of more than 100 alleles of storage proteins in wild species provide candidate genes for future quality improvement; (3) The documentation of quality effects of individual LMW-GS and HMW-GS for improving end-use quality; and (4) The analysis of α-gliadin genes on chromosomes 6A and 6D with non-toxic epitopes as potential targets to develop less toxic cultivars for people with celiac disease. Genomic and proteomic technologies that will continue to provide new tools for understanding variation and function of seed storage proteins in wheat are discussed. © 2014 Elsevier Ltd.

Liu Y.,Chinese Academy of Agricultural Sciences | He Z.,Chinese Academy of Agricultural Sciences | He Z.,International Maize and Wheat Improvement Center China Office | Appels R.,Murdoch University | Xia X.,Chinese Academy of Agricultural Sciences
Theoretical and Applied Genetics | Year: 2012

Functional markers (FM) are developed from sequence polymorphisms present in allelic variants of a functional gene at a locus. FMs accurately discriminate alleles of a targeted gene, and are ideal molecular markers for marker-assisted selection in wheat breeding. In this paper, we summarize FMs developed and used in common wheat. To date, more than 30 wheat loci associated with processing quality, agronomic traits, and disease resistance, have been cloned, and 97 FMs were developed to identify 93 alleles based on the sequences of those genes. A general approach is described for isolation of wheat genes and development of FMs based on in silico cloning and comparative genomics. The divergence of DNA sequences of different alleles that affect gene function is summarized. In addition, 14 molecular markers specific for alien genes introduced from common wheat relatives were also described. This paper provides updated information on all FMs and gene-specific STS markers developed so far in wheat and should facilitate their application in wheat breeding programs. © 2012 Springer-Verlag.

Geng H.,Washington State University | Geng H.,Xinjiang Agricultural University | Beecher B.S.,Washington State University | He Z.,Chinese Academy of Agricultural Sciences | And 3 more authors.
Theoretical and Applied Genetics | Year: 2012

Kernel texture is a major factor influencing the classification and end use properties of wheat (Triticum aestivum L.), and is mainly controlled by the Puroindoline a (Pina) and Puroindoline b (Pinb) genes. Recently, a new puroindoline gene, Puroindoline b-2 (Pin b-2), was identified. In this study, 388 wheat cultivars and advanced breeding lines from the U. S. Pacific Northwest were investigated for frequencies of Puroindoline D1 alleles and Pinb-2 variants 2 and 3. Results indicated that Pinb-D1b (74.0%) was the predominant genotype among hard wheats (N = 196), the only other hard allele encountered was Pina-D1b (26. 0%). Across all varieties, Pinb-2v3 was the predominant genotype (84.5%) compared with Pinb-2v2 (15.5%). However, among 240 winter wheat varieties (124 soft white, 15 club, 68 hard red and 33 hard white varieties), all carried Pinb-2v3. Among spring wheats, Pinb-2v2 and Pinb-2v3 frequencies were more variable (soft white 25.0:75.0, hard red 58.2:41.8 and hard white 40.0:60.0, respectively). Kernel texture variation was analyzed using 247 of the 388 wheat varieties grown in multi-location factorial trials in up to 7 crop years. The range of variety means among the four groups, soft winter, soft spring, hard winter and hard spring, was on the order of 15-25 single kernel characterization system (SKCS) Hardness Index. The least significant difference for each of these trials ranged from 2. 8 to 5.6 SKCS Hardness Index. Observations lead to the conclusion that Pinb-2 variants do not exert a prominent effect on kernel texture, however, Pinb-2 variants do identify features of wheat germ plasm structure in the U. S. Pacific Northwest. © 2012 Springer-Verlag (outside the USA).

Rasheed A.,Chinese Academy of Agricultural Sciences | Rasheed A.,Quaid-i-Azam University | Xia X.,Chinese Academy of Agricultural Sciences | Ogbonnaya F.,Grain Research and Development Corporation GRDC | And 5 more authors.
BMC Plant Biology | Year: 2014

Background: Grain size and shape greatly influence grain weight which ultimately enhances grain yield in wheat. Digital imaging (DI) based phenomic characterization can capture the three dimensional variation in grain size and shape than has hitherto been possible. In this study, we report the results from using digital imaging of grain size and shape to understand the relationship among different components of this trait, their contribution to enhance grain weight, and to identify genomic regions (QTLs) controlling grain morphology using genome wide association mapping with high density diversity array technology (DArT) and allele-specific markers.Results: Significant positive correlations were observed between grain weight and grain size measurements such as grain length (r = 0.43), width, thickness (r = 0.64) and factor from density (FFD) (r = 0.69). A total of 231 synthetic hexaploid wheats (SHWs) were grouped into five different sub-clusters by Bayesian structure analysis using unlinked DArT markers. Linkage disequilibrium (LD) decay was observed among DArT loci > 10 cM distance and approximately 28% marker pairs were in significant LD. In total, 197 loci over 60 chromosomal regions and 79 loci over 31 chromosomal regions were associated with grain morphology by genome wide analysis using general linear model (GLM) and mixed linear model (MLM) approaches, respectively. They were mainly distributed on homoeologous group 2, 3, 6 and 7 chromosomes. Twenty eight marker-trait associations (MTAs) on the D genome chromosomes 2D, 3D and 6D may carry novel alleles with potential to enhance grain weight due to the use of untapped wild accessions of Aegilops tauschii. Statistical simulations showed that favorable alleles for thousand kernel weight (TKW), grain length, width and thickness have additive genetic effects. Allelic variations for known genes controlling grain size and weight, viz. TaCwi-2A, TaSus-2B, TaCKX6-3D and TaGw2-6A, were also associated with TKW, grain width and thickness. In silico functional analysis predicted a range of biological functions for 32 DArT loci and receptor like kinase, known to affect plant development, appeared to be common protein family encoded by several loci responsible for grain size and shape.Conclusion: Conclusively, we demonstrated the application and integration of multiple approaches including high throughput phenotyping using DI, genome wide association studies (GWAS) and in silico functional analysis of candidate loci to analyze target traits, and identify candidate genomic regions underlying these traits. These approaches provided great opportunity to understand the breeding value of SHWs for improving grain weight and enhanced our deep understanding on molecular genetics of grain weight in wheat. © 2014 Rasheed et al.; licensee BioMed Central Ltd.

Xiao Y.G.,Chinese Academy of Agricultural Sciences | Xiao Y.G.,Northwest University, China | Qian Z.G.,Shandong Academy of Agricultural Sciences | Wu K.,Shandong Academy of Agricultural Sciences | And 5 more authors.
Crop Science | Year: 2012

Knowledge on the changes in yield potential and associated physiological traits is essential for understanding the main yield-limiting factors and guiding future breeding strategies. Our objective was to identify physiological traits associated with genetic gains in grain yield of winter wheat (Triticum aestivum L.) in Shandong province, China. Thirteen milestone cultivars and two advanced lines released from 1969 to 2006 were examined over 3 yr at Tai'an during 2006 to 2009. The genetic gain in grain yield was 62 kg ha-1 yr-1, largely associated with increased kernels per square meter, biomass, and harvest index (HI) and reduced plant height. Significant genetic changes were also observed especially for apparent leaf area index (LAI) at heading and anthesis, chlorophyll content (Chl) at anthesis, photosynthesis rate during grain filling, and stem water-soluble carbohydrate (WSC) content at anthesis. Comparing genotypes having Rht-D1b and others with both Rht-D1b and Rht8c (Rht-D1b+Rht8c) showed increased grain yield, thousand kernel weight, kernels per spike, kernel weight per spike, HI, canopy temperature depression, and Chl at anthesis and LAI at heading with the latter but no difference in height. The results suggested that genetic gains in grain yield in Shandong province were mainly contributed by increases in kernels per square meter and biomass, which were achieved through improving crop photosynthesis at and after heading, and the source for grain filling may have benefited from increased WSC in stems at anthesis. © Crop Science Society of America.

Zhang X.,Chinese Academy of Agricultural Sciences | Zhang X.,CAS Institute of Genetics and Developmental Biology | Jin H.,Chinese Academy of Agricultural Sciences | Zhang Y.,Chinese Academy of Agricultural Sciences | And 6 more authors.
BMC Plant Biology | Year: 2012

Background: Low-molecular-weight glutenin subunits (LMW-GS) strongly influence the bread-making quality of bread wheat. These proteins are encoded by a multi-gene family located at the Glu-A3, Glu-B3 and Glu-D3 loci on the short arms of homoeologous group 1 chromosomes, and show high allelic variation. To characterize the genetic and protein compositions of LMW-GS alleles, we investigated 16 Aroona near-isogenic lines (NILs) using SDS-PAGE, 2D-PAGE and the LMW-GS gene marker system. Moreover, the composition of glutenin macro-polymers, dough properties and pan bread quality parameters were determined for functional analysis of LMW-GS alleles in the NILs.Results: Using the LMW-GS gene marker system, 14-20 LMW-GS genes were identified in individual NILs. At the Glu-A3 locus, two m-type and 2-4 i-type genes were identified and their allelic variants showed high polymorphisms in length and nucleotide sequences. The Glu-A3d allele possessed three active genes, the highest number among Glu-A3 alleles. At the Glu-B3 locus, 2-3 m-type and 1-3 s-type genes were identified from individual NILs. Based on the different compositions of s-type genes, Glu-B3 alleles were divided into two groups, one containing Glu-B3a, B3b, B3f and B3g, and the other comprising Glu-B3c, B3d, B3h and B3i. Eight conserved genes were identified among Glu-D3 alleles, except for Glu-D3f. The protein products of the unique active genes in each NIL were detected using protein electrophoresis. Among Glu-3 alleles, the Glu-A3e genotype without i-type LMW-GS performed worst in almost all quality properties. Glu-B3b, B3g and B3i showed better quality parameters than the other Glu-B3 alleles, whereas the Glu-B3c allele containing s-type genes with low expression levels had an inferior effect on bread-making quality. Due to the conserved genes at Glu-D3 locus, Glu-D3 alleles showed no significant differences in effects on all quality parameters.Conclusions: This work provided new insights into the composition and function of 18 LMW-GS alleles in bread wheat. The variation of i-type genes mainly contributed to the high diversity of Glu-A3 alleles, and the differences among Glu-B3 alleles were mainly derived from the high polymorphism of s-type genes. Among LMW-GS alleles, Glu-A3e and Glu-B3c represented inferior alleles for bread-making quality, whereas Glu-A3d, Glu-B3b, Glu-B3g and Glu-B3i were correlated with superior bread-making quality. Glu-D3 alleles played minor roles in determining quality variation in bread wheat. Thus, LMW-GS alleles not only affect dough extensibility but greatly contribute to the dough resistance, glutenin macro-polymers and bread quality. © 2012 Zhang et al.; licensee BioMed Central Ltd.

Zhang H.,Agricultural University of Hebei | Xia X.,Chinese Academy of Agricultural Sciences | He Z.,Chinese Academy of Agricultural Sciences | He Z.,International Maize and Wheat Improvement Center China Office | And 3 more authors.
Molecular Breeding | Year: 2011

Leaf rust, caused by Puccinia triticina, is one of the most widespread diseases in common wheat (Triticum aestivum L.) globally. With the objective of identifying and mapping new genes for resistance to leaf rust, F1, F2 plants and F3 lines from a cross between resistant cultivar Bimai 16 and susceptible cultivar Thatcher were inoculated with Chinese Puccinia triticina pathotypes FHTT and PHTS in the greenhouse. In the first seedling test, Bimai 16, Thatcher, 20 F1 plants, 359 F2 plants and 298 F3 lines were inoculated with pathotype FHTT. A set of 1,255 simple sequence repeat (SSR) primer pairs were used to test the parents, and resistant and susceptible bulks. Seven polymorphic markers on chromosome 7BL were used for genotyping the F2 and F3 populations. The results indicated that Bimai 16 carried a single dominant resistance gene, temporarily designated LrBi16, closely linked to SSR markers Xcfa2257 and Xgwm344, with genetic distances of 2. 8 and 2. 9 cM, respectively. In the second seedling test, two dominant resistance genes were identified in Bimai 16 based on seedling reactions of 254 F2 plants inoculated with pathotype PHTS. One of the genes was LrBi16, and the other was likely to be LrZH84, which is located in chromosome 1BL. The seedling reaction pattern of plants with LrBi16 was different from that of the Thatcher lines, with Lr14a and Lr14b located on chromosome 7BL. It was concluded that LrBi16 is likely to be a new leaf rust resistance gene. © 2010 Springer Science+Business Media B.V.

Zhang Y.,Chinese Academy of Agricultural Sciences | Zhang Y.,Hebei Academy of Agricultural and Forestry science | Miao X.,Chinese Academy of Agricultural Sciences | Xia X.,Chinese Academy of Agricultural Sciences | And 2 more authors.
Theoretical and Applied Genetics | Year: 2014

Key message: After cloning and mapping of wheat TaSdr genes, both the functional markers for TaSdr - B1 and TaVp - 1B were validated, and the distribution of allelic variations at TaSdr - B1 locus in the wheat cultivars from 19 countries was characterized. Seed dormancy is a major factor associated with pre-harvest sprouting (PHS) in common wheat (Triticum aestivum L.). Wheat TaSdr genes, orthologs of OsSdr4 conferring seed dormancy in rice, were cloned by a comparative genomics approach. They were located on homoeologous group 2 chromosomes, and designated as TaSdr-A1, TaSdr-B1 and TaSdr-D1, respectively. Sequence analysis of TaSdr-B1 revealed a SNP at the position -11 upstream of the initiation codon, with bases A and G in cultivars with low and high germination indices (GI), respectively. A cleaved amplified polymorphism sequence marker Sdr2B was developed based on the SNP, and subsequently functional analysis of TaSdr-B1 was conducted by association and linkage mapping. A QTL for GI co-segregating with Sdr2B explained 6.4, 7.8 and 8.7 % of the phenotypic variances in a RIL population derived from Yangxiaomai/Zhongyou 9507 grown in Shijiazhuang, Beijing and the averaged data from those environments, respectively. Two sets of Chinese wheat cultivars were used for association mapping, and results indicated that TaSdr-B1 was significantly associated with GI. Analysis of the allelic distribution at the TaSdr-B1 locus showed that the frequencies of TaSdr-B1a associated with a lower GI were high in cultivars from Japan, Australia, Argentina, and the Middle and Lower Yangtze Valley Winter Wheat Region and Southwest Winter Wheat Region in China. This study provides not only a reliable functional marker for molecular-assisted selection of PHS in wheat breeding programs, but also gives novel information for a comprehensive understanding of seed dormancy. © 2014 Springer-Verlag Berlin Heidelberg.

Zhang Y.,Chinese Academy of Agricultural Sciences | Zhang Y.,Hebei Academy of Agricultural and Forestry science | Liu J.,Chinese Academy of Agricultural Sciences | Xia X.,Chinese Academy of Agricultural Sciences | And 2 more authors.
Molecular Breeding | Year: 2014

The OsGS3 gene plays a principal role in controlling grain weight and grain length in rice. However, the function of an orthologous gene TaGS in wheat has not been analyzed to date. In the present study, we cloned the gDNA of TaGS gene, designated TaGS-D1, with four exons and three introns on chromosome 7DS by a comparative genomics approach. The cDNA of TaGS-D1 is 255 bp, and it encodes 85 amino acids. We also found a plant-specific organ size regulation domain in the deduced polypeptide, indicating that TaGS-D1, like OsGS3, does not belong to the PEBP family. DNA sequencing of the TaGS-D1 locus revealed no diversity in the coding sequence of exons, but there was a single nucleotide polymorphism (SNP) in the first intron, and 30 SNPs, a 40-bp InDel and a 3-bp InDel were found in the second intron between genotypes with higher and lower thousand grain weights (TGW). Based on the 40-bp InDel, a co-dominant STS marker, designated GS7D, was developed to discriminate the two alleles. GS7D was 8.0 cM from Xbarc184 located on chromosome 7DS by linkage mapping. A QTL for TGW and grain length at GS7D locus explained up to 16.3 and 7.7 %, respectively, of the phenotypic variances in a RIL population derived from Doumai/Shi 4185 grown in Shijiazhuang and Beijing. One hundred and seventy-five Chinese wheat cultivars were genotyped with GS7D, indicating that TaGS-D1 was significantly associated with grain weight. The allelic distribution at the TaGS-D1 locus showed that the frequencies of TaGS-D1a were high in cultivars from Serbia, Japan, Australia, Canada, and the Northeastern Spring Wheat and Northern Winter Wheat Regions of China. © 2014, Springer Science+Business Media Dordrecht.

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