The high molecular weight glutenin subunit （HMW-GS） pair 1Bx13＋1By16 are recognized to positively correlate with bread-making quality; however, their molecular data remain unknown. In order to reveal the mechanism ...The high molecular weight glutenin subunit （HMW-GS） pair 1Bx13＋1By16 are recognized to positively correlate with bread-making quality; however, their molecular data remain unknown. In order to reveal the mechanism by which 1By16 and 1Bx13 creates high quality, their open reading frames （ORFs） were amplified from common wheat Atlas66 and Jimai 20 using primers that were designed based on published sequences of HMW glutenin genes. The ORF of 1By16 was 2220bp, deduced into 738 amino acid residues with seven cysteines including 59 hexapeptides and 22 nanopeptides motifs. The ORF of 1Bx13 was 2385bp, deduced into 795 amino acid residues with four cysteines including 68 hexapeptides, 25 nanopeptides and six tripepUdes motifs. We found that 1By16 was the largest y-type HMW glutenin gene described to date in common wheat. The 1By16 had 36 amino acid residues inserted in the central repetitive domain compared with 1By15. Expression in bacteria and western-blot tests confirmed that the sequence cloned was the ORF of HMW-GS 1By16, and that 1Bx13 was one of the largest 1Bx genes that have been described so far in common wheat, exhibiting a hexapeptide （PGQGQQ） insertion in the end of central repetitive domain compared with 1Bx7. A phylogenetic tree based on the deduced full-length amino acid sequence alignment of the published HMW-GS genes showed that the 1By16 was clustered with Glu-1B-2, and that the 1Bx13 was clustered with Glu-1B-1 alleles.展开更多
Wheat processing quality is greatly influenced by the seed proteins especially the high molecular weight glutenin subunit (HMW-GS) components, the low molecular weight glutenin subunit (LMW-GS) components and gliadin ...Wheat processing quality is greatly influenced by the seed proteins especially the high molecular weight glutenin subunit (HMW-GS) components, the low molecular weight glutenin subunit (LMW-GS) components and gliadin components. Genes encoding the HMW-GS and LMW-GS components were located on the long arms and the short arms of homoeologous group 1 chromosomes, respectively. HMW-GS components in 5 129 accessions of wheat germplasms were analyzed systematically, including 3 459 landraces and 1 670 modern varieties. These accessions were chosen as candidate core collections to represent the genetic diversity of Chinese common wheat ( Triticum aestivum) germplasms documented and conserved in the National Gene Bank. These candidate core collections covered the 10 wheat production regions in China. In the whole country, the dominating alleles at the three loci are Glu-A1b (null), Glu-B1b (7 + 8), and Glu-D1a (2 + 12), respectively. The obvious difference between the land race and the modern variety is the dramatic frequency increase of alleles Glu-A1a (1), Glu-B1c (7 + 9), Glu-B1h (14 + 15), Glu-D1d (5 + 10) and allele cording 5 + 12 subunits in the later ones. In the whole view, there is minor difference on the genetic(allelic)richness between the landrace and the modern variety at Glu-1, which is 28 and 30 respectively. However, the genetic dispersion index (Simpson index) based on allelic variation and frequencies at Glu-A1, Glu-B1 and Glu-D1 suggested that the modern varieties had much higher genetic diversity than the landraces. This revealed that various isolating mechanisms (such as auto-gamous nature, low migration because of undeveloped transposition system) limited the gene flow and exchange between populations of the landraces, which led up to some genotypes localized in very small areas. Modern breeding has strongly promoted gene exchanges and introgression between populations and previous isolated populations. In the three loci, Glu-Bl has the highest genetic diversity , then Glu-D1, while Glu-A1 always ke展开更多
Loss of variety resistance to stripe rust （Puccinia striiformis Westend f. sp.tritici） is an important factor causing massive periodical epidemic of rust in wheat production. Creation and development of new races of...Loss of variety resistance to stripe rust （Puccinia striiformis Westend f. sp.tritici） is an important factor causing massive periodical epidemic of rust in wheat production. Creation and development of new races of rust pathogen have led to serious crisis of resistance loss in widely planted varieties. This has quickened the search for new resistance resources. Molecular marker could facilitate the identification of the location of novel genes. A line A-3 with high resistance （immune） to currently epidemic yellow rust races （CY29, 31, 32） was screened out in offspring of Triticum aestivura x Thinopyrum ponticum. Segregation in F2 and BC1 populations indicated that the resistance was controlled by two independent genes： one dominant and one recessive. SSR markers were employed to map the two resistant genes in the F2 and BC1 populations. A marker WMC477-167bp located on 2BS was linked to the dominant gene with genetic distance of 0.4 cM. Another marker WMC364-2os bp located on 7BS was linked to the recessive-resistant gene with genetic distance of 5.8 cM. The two genes identified in this paper might be two novel stripe rust resistant genes, which were temporarily designated as YrTpl and YrTp2, respectively. The tightly linking markers facilitate transfer of the two resistant genes into the new varieties to control epidemic of yellow rust.展开更多
Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair ...Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair of varieties grown side-by-side, is time-consuming and is not suitable for the assessment of hundreds of samples. The objective of this study was to develop a procedure for the assessment of wheat variety distinctness using simple sequence repeat（SSR） markers. A comparison between the molecular and morphological profile of 797 varieties was made. On the basis of the comparison, pairs of varieties with a genetic similarity value（GSV） ≤90% were deemed to be distinct, accounting for ~85% of varieties assessed in wheat regional trials. For the remaining ~15% of varieties, GSVs between different varieties were 〉90%, among which ~35% were not distinct and the other ~65% were distinct. Therefore, if given a GSV〉90%, the pairs of varieties should be morphologically assessed in the field. To avoid any errors in the assessments, we proposed the elimination of contaminant plants from the sample before comparing the varietal genotypes, scoring of the genotype at each locus with a pair of allele numbers when constructing a molecular profile, and faithfully recording two alleles at a non-homozygous locus. To reduce the workload and cost, a three-grade markers comparison among varieties is suggested. In addition, 80 SSR markers and a technical procedure for assessment of wheat variety distinctness have been proposed. Based on the procedure, the distinctness assessment of ~85% of all wheat varieties is completed in our laboratory annually. Consequently, total field assessment has been reduced considerably.展开更多
基金the National Natural Science Foundation of China (30671293)the High-Tech Research and Development (863) Program of China(2006AA100102).
文摘The high molecular weight glutenin subunit （HMW-GS） pair 1Bx13＋1By16 are recognized to positively correlate with bread-making quality; however, their molecular data remain unknown. In order to reveal the mechanism by which 1By16 and 1Bx13 creates high quality, their open reading frames （ORFs） were amplified from common wheat Atlas66 and Jimai 20 using primers that were designed based on published sequences of HMW glutenin genes. The ORF of 1By16 was 2220bp, deduced into 738 amino acid residues with seven cysteines including 59 hexapeptides and 22 nanopeptides motifs. The ORF of 1Bx13 was 2385bp, deduced into 795 amino acid residues with four cysteines including 68 hexapeptides, 25 nanopeptides and six tripepUdes motifs. We found that 1By16 was the largest y-type HMW glutenin gene described to date in common wheat. The 1By16 had 36 amino acid residues inserted in the central repetitive domain compared with 1By15. Expression in bacteria and western-blot tests confirmed that the sequence cloned was the ORF of HMW-GS 1By16, and that 1Bx13 was one of the largest 1Bx genes that have been described so far in common wheat, exhibiting a hexapeptide （PGQGQQ） insertion in the end of central repetitive domain compared with 1Bx7. A phylogenetic tree based on the deduced full-length amino acid sequence alignment of the published HMW-GS genes showed that the 1By16 was clustered with Glu-1B-2, and that the 1Bx13 was clustered with Glu-1B-1 alleles.
文摘Wheat processing quality is greatly influenced by the seed proteins especially the high molecular weight glutenin subunit (HMW-GS) components, the low molecular weight glutenin subunit (LMW-GS) components and gliadin components. Genes encoding the HMW-GS and LMW-GS components were located on the long arms and the short arms of homoeologous group 1 chromosomes, respectively. HMW-GS components in 5 129 accessions of wheat germplasms were analyzed systematically, including 3 459 landraces and 1 670 modern varieties. These accessions were chosen as candidate core collections to represent the genetic diversity of Chinese common wheat ( Triticum aestivum) germplasms documented and conserved in the National Gene Bank. These candidate core collections covered the 10 wheat production regions in China. In the whole country, the dominating alleles at the three loci are Glu-A1b (null), Glu-B1b (7 + 8), and Glu-D1a (2 + 12), respectively. The obvious difference between the land race and the modern variety is the dramatic frequency increase of alleles Glu-A1a (1), Glu-B1c (7 + 9), Glu-B1h (14 + 15), Glu-D1d (5 + 10) and allele cording 5 + 12 subunits in the later ones. In the whole view, there is minor difference on the genetic(allelic)richness between the landrace and the modern variety at Glu-1, which is 28 and 30 respectively. However, the genetic dispersion index (Simpson index) based on allelic variation and frequencies at Glu-A1, Glu-B1 and Glu-D1 suggested that the modern varieties had much higher genetic diversity than the landraces. This revealed that various isolating mechanisms (such as auto-gamous nature, low migration because of undeveloped transposition system) limited the gene flow and exchange between populations of the landraces, which led up to some genotypes localized in very small areas. Modern breeding has strongly promoted gene exchanges and introgression between populations and previous isolated populations. In the three loci, Glu-Bl has the highest genetic diversity , then Glu-D1, while Glu-A1 always ke
文摘Loss of variety resistance to stripe rust （Puccinia striiformis Westend f. sp.tritici） is an important factor causing massive periodical epidemic of rust in wheat production. Creation and development of new races of rust pathogen have led to serious crisis of resistance loss in widely planted varieties. This has quickened the search for new resistance resources. Molecular marker could facilitate the identification of the location of novel genes. A line A-3 with high resistance （immune） to currently epidemic yellow rust races （CY29, 31, 32） was screened out in offspring of Triticum aestivura x Thinopyrum ponticum. Segregation in F2 and BC1 populations indicated that the resistance was controlled by two independent genes： one dominant and one recessive. SSR markers were employed to map the two resistant genes in the F2 and BC1 populations. A marker WMC477-167bp located on 2BS was linked to the dominant gene with genetic distance of 0.4 cM. Another marker WMC364-2os bp located on 7BS was linked to the recessive-resistant gene with genetic distance of 5.8 cM. The two genes identified in this paper might be two novel stripe rust resistant genes, which were temporarily designated as YrTpl and YrTp2, respectively. The tightly linking markers facilitate transfer of the two resistant genes into the new varieties to control epidemic of yellow rust.
基金funded by the Innovation Platform for Basic Research in Breeding of Beijing, China (D08070500690801)the Science and Technology Innovation Ability Construction Projects,Beijing Academy of Agricultural and Forestry Sciences, China (KJCX20140202)
文摘Assessment of variety distinctness is important for both the registration and the protection of particular variety. However, the current testing system, which assesses a range of morphological characters of each pair of varieties grown side-by-side, is time-consuming and is not suitable for the assessment of hundreds of samples. The objective of this study was to develop a procedure for the assessment of wheat variety distinctness using simple sequence repeat（SSR） markers. A comparison between the molecular and morphological profile of 797 varieties was made. On the basis of the comparison, pairs of varieties with a genetic similarity value（GSV） ≤90% were deemed to be distinct, accounting for ~85% of varieties assessed in wheat regional trials. For the remaining ~15% of varieties, GSVs between different varieties were 〉90%, among which ~35% were not distinct and the other ~65% were distinct. Therefore, if given a GSV〉90%, the pairs of varieties should be morphologically assessed in the field. To avoid any errors in the assessments, we proposed the elimination of contaminant plants from the sample before comparing the varietal genotypes, scoring of the genotype at each locus with a pair of allele numbers when constructing a molecular profile, and faithfully recording two alleles at a non-homozygous locus. To reduce the workload and cost, a three-grade markers comparison among varieties is suggested. In addition, 80 SSR markers and a technical procedure for assessment of wheat variety distinctness have been proposed. Based on the procedure, the distinctness assessment of ~85% of all wheat varieties is completed in our laboratory annually. Consequently, total field assessment has been reduced considerably.
