The Molecular Mechanism Of ZmVPS29 Regulating Maize Kernel Size And The Construction Of Genetic Regulatory Network

Maize is the important food,feed,energy crops in the world.Improving the biomass,grain yield and quality is the goal of maize genetic improvement and breeding.Analysis of multi-gene regulatory network can provide important supports for high-yield breeding of maize.Based on the former study of our lab,a major QTL for KM,qKM4.08,was cloned by linkage analysis and identified the important candidate gene,Zm VPS29.In this study,overexpression of Zm VPS29 in different genetic backgrounds can significantly decrease the kernel widtth,but the yield per plant is significantly increased.Overexpression of ZmVPS29 can change the expression of auxin related genes,thus affecting the distribution of auxin in the developing kernels.Zm VPS29 encodes a vacuole sorting protein,which was proven to interact with ZmVps26a and ZmVps35a and participate in auxin network regulation.The results of association analysis showed that S-1830(G/A variation)and S-1558(GA insertion variation)located in the promoter region of ZmVPS29 gene were significantly correlated with the kernel size.The results of evolutionary analysis showed that S-1830 and S-1558 were strongly selected in the process of maize domestication and improvement.With the support of the major research program of NSFC and in collaboration with Huazhong Agricultural University,Henan Agricultural University and Harbin University of technology,the genotypes which pyramiding the favorable haplotypes of the Zm VPS29.ZmKL9(key genes of grain length,cloned by Huazhong Agricultural University)and Urb2(key gene of grain thickness,cloned by Henan Agricultural University)have been development in this project.And obvious additive effects for the favorable haplotypes of targeting genes were observed on maize kernel size related traits.However,different haplotypes have different effects on different kernel related traits,which reflects the complex relationship between kernel related traits.The research method of construction and fusion of multi combination weighted network was developed The method of construction and fusion of multi-combination weighted network was developed.Using public dataset,the co-expression regulatory network of maize kernel development across multi-stages,was constructed,which includes 288 homologous in other plants and 41 maize kernel development related genes.Moreover,using the expression profiles of immature kernels at 6 DAP,a co-expression regulatory network tightly connected with kernel size was constructed,which includes 148 homologous and maize kernel development related genes,such as emp7,emp12,Zmsweet4c.The outcomes from the project will provide novel ideas and technologies for the dissection of regulatory network for the complex traits in crops.Meanwhile,in this project,all the primary mapping populations have come from the field breeding practice.Therefore,the discovered elite haplotypes will be easily applied.Finally,the results of this project will also provide theoretical and technical insights to the improvement of the kernel shape related traits in maize.