Fine Mapping Of A Leaf Early Senescence Gene Y1718 In Common Wheat

Wheat(Triticum aestivum L.)Leaves are the important organs for photosynthesis.The premature senescence of leaf seriously affects the time and efficiency of plant photosynthesis,which restricts the yield and quality of crops.With the continuous decrease of agricultural arable land in China,increasing wheat output is an urgent problem to be solved in wheat production.Wheat premature aging mutants are ideal materials for studying the molecular mechanism of wheat senescence.The leaf senescence mutant Ygm is a natural leaf premature mutant discovered by the laboratory.The leaf premature trait is controlled by an incomplete dominant nuclear gene(Y1718).There are three types of senescence phenotypes in its inbred offspring:premature(Y),Semi-early maturity type(Yg)and normal aging type(G).In this experiment,the Yg type of mutant Ygm was crossed with Shannong extra large grains to create a localized population of 1200 strains.Through Bulked Segregant Analysis(BSA)and wheat 660 K chip analysis combined with the phenotype data,the genetic mapping of the target gene Y1718 and the preliminary prediction of candidate genes were determined.It lays the foundation for the cloning of wheat leaf senescence mutant genes.The main results were as follows:1.Field observations of the three senescent phenotypes of the mutant Ygm inbred progeny throughout the growth period revealed that the leaves of the fully premature senescence type Y plant appeared yellow-green at the seedling stage,and with the growth and development,the entire plant was completely Yellowing,the plants gradually die,and no seeds can be formed;the leaf color of the early-senescence Yg plant is similar to the normal senescence G plant at the seedling stage,and they are all green,but the newly developed leaves are yellow-green after the greening and jointing stage in winter,and the heading and flowering stages Before and after the leaves,stems,and ears gradually showed yellow stripes of varying degrees,but the plant height was similar to that of the normal senescent G-strain,and it could be normally sturdy.Genetic analysis showed that the leaf senescence mutant Ygm was controlled by a pair of incomplete dominant genes,which further confirmed that the leaf premature trait of the mutant was controlled by an incomplete dominant nuclear gene Y1718.2.Genetic analysis showed that the leaf senescence mutant Ygm was controlled by apair of incomplete dominant nuclear genes,which further confirmed that the leaf early senescence trait of the mutant was controlled by an incomplete dominant nuclear gene Y1718.3.The mutant gene Y1718 on chromosome 2DS by BSA combined with wheat660 K SNP chip,the genetic distances between TC89539 and Xmag4271 molecule markers are 0.7c M and 0.7c M respectively,and it is separated from Xwmc25.The candidate genes of Y1718 were preliminarily predicted in the target segment,and the functional annotation were Glycosyltransferase 、 rginine/serine-rich splicing factor、Gibberellin-regulated family protein respectively.