异源三聚体G蛋白通过调控信号传递介导生物体生长发育，Gγ亚基决定了细胞信号转导的特异性。我们的研究表明，不同于拟南芥和水稻，小麦TaGS3 (Gγ) 存在5种RNA剪接形式，产生5种不同的蛋白质。.本课题利用 TaGS3不同染色体组同源基因(TaGS3-A、TaGS3-B和TaGS3-D)的缺失突变体进行籽粒大小的表型分析，明确同源基因生物学功能差异及位点间的协同作用；通过分析TaGS3不同剪接形式的转基因植株籽粒性状，筛选出对小麦籽粒大小起正向调控作用的剪接形式；通过酵母双/三杂交、BiFC等手段检测不同剪接形式与Gα和Gβ的结合能力，阐明TaGS3不同剪接形式参与小麦籽粒大小调控的作用机制；利用微核心种质、KJ-RIL及育成品种群体，发掘TaGS3优异等位变异，开发功能标记用于分子育种。.研究结果将丰富多倍体小麦基因功能分化和调控的理论体系，更为分子育种提供基因资源和功能性分子标记。

Heterotrimeric G-protein mediates growth and development by perceiving and transmitting signals in multiple organisms. Gγ subunit determines the specificity of the signal transduction pathways. Our previous results revealed that there are five splicing isoforms of TaGS3 (Gγ), which translate five proteins with different domains, whereas alternative splicing has not been reported in Arabidopsis and rice. It is speculated that alternative splicing of TaGS3 may be an important regulation pattern invloved in kernel traits in wheat..Common wheat is an allohexaploid grass species (AABBDD, 2n=6x=42). Our project will focus on: First, ion beam-induced mutant library was used to select three TaGS3 homoeologs single mutants which are crossed each other to obtain the double and triple mutants for analyzing the grain size. The results obtained from these mutants will be helpful to clarify the function diversity of the three TaGS3 homoeologs (TaGS3-A, TaGS3-B and TaGS3-D) and the collaborative relationship between homoeologous genes. Second, transgenic wheat lines harboring different splicing isoforms of TaGS3 will be used to analyze the kernel traits and identify the splicing isoform which positively regulates the grain size. Using yeast-two/three hybrid and BiFC, the combining ability of splicing isoforms of TaGS3 with Gα and Gβ will be investigated. Third, using MCC, KJ-RIL and bred variety population, the haplotypes and allelic variation of TaGS3 will be studied and functional molecular markers of TaGS3 favorable haplotypes will be developed. Eventually, our work will provide gene resources and functional markers in molecular breeding to improve kernel weight in common wheat.