Studies On Whole Genome Methylation And Proteomics During Feritility Transition In Rice Wuxiang S

The fertility transition of a PTGMS line rice Wuxiang S(WXS)is affected by environmental conditions,such as temperature and day length.This effect is universal in two-line hybrid rice.At present,no detailed research has yet been reported on the molecular basis of fertility conversion in WXS from the perspective of proteomics and genomic level.Therefore,in order to explore the molecular mechanism and protein regulatory network of PTGMS rice fertility conversion,young panicle at the critical phase of WXS fertility transition were selected as research material,the sterile and fertile plant proteomics were compared,integrative analysis of proteomics and transcriptomics was performed,genome-wide methylation analysis was conducted.The main results were as follows:1.Protein expression profiles of WXS young panicles at pollen mother cell formation phase(P2)and meiosis phase(P3)were obtained by using iTRAQ quantitative proteomics technology.The results showed that a total of 340 differential expressed proteins were identified at the critical period of fertility transformation between the sterile plant Wuxiang S(S)and the fertile plant Wuxiang S(F).At the pollen mother cell formation phase(P2),263 DEPs were identified from the comparison between FP2 and SP2,of which 119 were up-regulated and 144 were down-regulated.At meiosis phase(P3),249 DEPs were screened when FP3 compared with SP3,of which 87 were up-regulated and 162 were down-regulated.GO and KEGG enrichment analysis of DEPs revealed that they were involved in energy metabolism pathway and pollen wall development pathway.These DEPs may play an important role in the process of WXS fertility transformation.2.Correlation analysis between proteomic data and transcriptome data revealed that 92 differentially expressed genes(DEGs)have corresponding differentially expressed proteins in the pollen mother cell formation phase(P2).By comparing the correlation between DEGs and corresponding DEPs,it was found that 27 genes and proteins were up-regulated consistently,and 39 genes were down-regulated consistently with their proteins.In the meiosis phase(P3),71 differential expressed genes have corresponding differential expressed proteins.It was found that 6 genes and corresponding proteins were up-regulated together,and 50 genes and corresponding proteins were down-regulated together.Cor-DEGs-DEPs(corresponding DEGs and DEPs),among which coincident trend was existed between gene and the corresponding proteins,were analyzed by GO and KEGG functional enrichment.It was found that cor-DEGs-DEPs were involved in plant hormone signal transduction,endoplasmic reticulum protein processing,starch and sucrose metabolism,phenyl-propion biosynthesis,keratin,flavin and wax biosynthesis.These cor-DEGs-DEPs constituted a complex network system that may regulate WXS fertility transition.3.Whole Genome Bisulfite Sequencing(WGBS)was used to analyze the genome-wide DNA methylation state of WXS(F)and WXS(S)during pollen mother cell formation phase(P2)and meiosis phase(P3).The results showed that the whole genome methylation levels of SP2,SP3,FP2 and FP3 were 2.47%,22.73%,23.73% and 24.84%,respectively.In the CG sequence environment,3628 differentially methylated region genes(DMGs)were obtained when SP2 compared with FP2,4576 DMGs were screened by comparison between SP3 and FP3.In the CHG sequence environment,there were 2075 DMGs when SP2 compared with FP2,3274 DMGs when SP3 compared with FP3;in the CHH sequence environment,124 DMGs were acquired when SP2 compared with FP2,225 DMGs were gained when SP3 compared with FP3.GO and KEGG enrichment analysis of DMGs were performed and genes that may be associated with WXS fertility transition were explored.