Transcriptome Analysis Of Developing Kernel About Two Maize Inbred Lineswith Different Kernel Shape

Seed size and kernel weight are important components of maize grain yield, and have been reagarded asgreat targets for genetic improvement. In this study, two maize inbred lines with distinct seed size and weight, V671(large seed inbred line) and Me (small seed inbred line), was investigated by RNA-seq at two important developmental stage (9DAP (Days after pollination) and14DAP). The investigation and measurement of V671and Mc phenotype during seed development were combined together with RNA-seq results, trying to uncover the reason of the difference between V671and Mc kernels. The main results are as follows.1. The seed size and kernel weight difference between Mc and V671were much more significant in some environments than in others, phenotopic difference was highest under Sanya.Reciprol cross between Mc and V671showed that maternal control is not the only factor that determines maize seed size and kernel weight, the genotype of zygote(endosperm and embryo) can also have an influence on maize kernels. Based on the investigation on kernel width increasing pattern, V671possesses a higher increasing rate and longer increasing time period than Mc.2. The results of RNA-seq showed that Mc was higher in storage accumulation activity while V671possesses more higher-expressed genes on cell peoliferation and DNA duplication.3. The gene expression pattern analysis revealed that IAA synthesis genes expression increased earlier in Mc and the expression of mitosis genes were weaker than V671.We concluded that IAA concentration rise earlier in Mc kernels, which can lead to an earlier entrance into grain filling.4. RNA-seq data, qRT-PCR and the phenotype investigation demonstrated that Mc develops faster than V671, accumulates earlier in Mcwhich leads to a less endosperm cell number and a smaller sink at maturity. This may the reason why Mc is smaller than V671.