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Cloning of TaSST genes associated with water soluble carbohydrate content in bread wheat stems and development of a functional marker

Dong, Yan, Zhang, Yan, Xiao, Yonggui, Yan, Jun, Liu, Jindong, Wen, Weie, Zhang, Yong, Jing, Ruilian, Xia, Xianchun, He, Zhonghu
Theoretical and applied genetics 2016 v.129 no.5 pp. 1061-1070
Triticum aestivum, alleles, biochemical pathways, breeding, carbohydrate content, chromosomes, cultivars, exons, fructans, genetic distance, genetic markers, inbred lines, quantitative trait loci, sequence analysis, single nucleotide polymorphism, stems, wheat, China
KEY MESSAGE: We cloned TaSST genes, developed a gene-specific marker for TaSST - D1 , and identified three QTL in the Doumai/Shi 4185 RIL population. TaSST - D1 is within one of the three QTL. Sucrose:sucrose-1-fructosyltransferase (1-SST), a critical enzyme in the fructan biosynthetic pathway, is significantly and positively associated with water soluble carbohydrate (WSC) content in bread wheat stems. In the present study, wheat 1-SST genes (TaSST) were isolated and located on chromosomes 4A, 7A and 7D. Sequence analysis of TaSST-D1 revealed 15 single nucleotide polymorphisms (SNP) in the third exon between cultivars with higher and lower WSC content. A cleaved amplified polymorphism sequence (CAPS) marker, WSC7D, based on the polymorphism at position 1216 (C-G) was developed to discriminate the two alleles. WSC7D was located on chromosome 7DS using a recombinant inbred line (RIL) population from a Doumai/Shi 4185 cross, and a set of Chinese Spring nullisomic-tetrasomic lines. TaSST-D1 co-segregated with the CAPS marker WSC7D and was linked to SNP marker BS00108793_51 on chromosome 7DS at a genetic distance of 6.1 cM. It explained 8.8, 10.9, and 11.3 % of the phenotypic variances in trials at Beijing and Shijiazhuang as well as the averaged data from those environments, respectively. Two additional QTL (QWSC.caas-4BS and QWSC.caas-7AS) besides TaSST-D1 were mapped in the RIL population. One hundred and forty-nine Chinese wheat cultivars and advanced lines tested in four environments were used to validate a highly significant (P < 0.01) association between WSC7D and WSC content in wheat stems. WSC7D can be used as a gene-specific marker for improvement of stem WSC content in wheat breeding programs.