RNA-Seq rawdata of JM22 and JM43

Apart from starch content, structure is also vital for the eating and nutritional qualities of final products. The study investigated how the starch structure changed during grain filling period using two wheat cultivars with different filling rate. The starch biosynthesis during grain filling was not at uniform speed and most of starches were synthesized before 19 DAF. The starch structure formation was non synchronous with starch biosynthesis, but the structure formed at early stage of grain filling was highly related to the final one. The process of starch biosynthesis was closely accompanied by the elongation of amylose chains, increase on branch numbers, B-type granule number and expansion of A-type granule. Further analysis on expression profiles of key genes involved in starch biosynthesis demonstrated that cultivar with higher filling rate showed more amount of related gene expression at 13 DAF and it was mainly GBSSI, participating in amylose elongation and exhibiting high plasticity in expression level, also leading to the changes on relative expression between starch-biosynthesis related members, thus resulting in difference on establishment of fine structure. The results will provide new insights to understanding the formation starch structure during grain filling, which may benefit future research on management and breeding.