| The content and structure of grain starch affect the wheat yield and quality. Starch synthase(SS) plays a key role in starch biosynthesis. SS genes are a multi-member family with different functional characteristics, forming by several times of gene duplication and function differentiation. In order to reveal the sequence characteristics and expression differences,the wheat SS genes were identified by referring the known rice SS protein sequences, and differential expression analysis were performed. The result showed that 27 SS genes were identified in wheat, and distributing on chromosomes of 1A/1B/1D, 2A/2B/2D, 6A/6B/6D, 7A/7B/7D. 27 SS genes could be divided into Group A and Group B, and Group A contained three subfamilies of TaGBSS, TaSSⅠ and TaSSⅡ, all GroupA members had motif1-motif10, and the motif order was consistent; Group B contained two subfamilies of TaSSⅢ and TaSSⅣ, both of which lacked motif9 and motif10. In addition, the TaSSⅢ subfamily also lacked motif8. Different from maize, rice, sorghum and Arabidopsis, SS genes of wheat did not contain TaSSⅤ subfamily.There were significant differences in gene expression among different gene copies in the same subfamily, TaGBSSⅠ, TaSSⅡa and TaSSⅢa were specifically expressed in endosperm.SS genes in the same partial homologous group of wheat were also expressed differently in different tissues and at different developmental stages, and the expression levels of TaSSⅡa-B and TaSSⅡa-D were higher than those of TaSSⅡa-A in endosperm at 20 and 30 days after pollination.The type and number of endosperm specific expression elements(RY-element,AACA-motif and ACGTOSGLUB1) in the SS gene promoters were different. |
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