Search

The regulation of female fertility is an important field of rice sexual reproduction research. DNA methylation is an essential epigenetic modification that dynamically regulates gene expression during development processes. However, few reports have described the methylation profiles of female-sterile rice during ovule development. In this study, ovules were continuously acquired from the beginning of megaspore mother cell meiosis until the mature female gametophyte formation period, and global DNA methylation patterns were compared in the ovules of a high-frequency female-sterile line (fsv1) and a wildtype rice line (Gui99) using whole-genome bisulfite sequencing (WGBS). Profiling of the global DNA methylation revealed hypo-methylation, and 3471 significantly differentially methylated regions (DMRs) were observed in fsv1 ovules compared with Gui99. Based on functional annotation and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis of differentially methylated genes (DMGs), we observed more DMGs enriched in cellular component, reproduction regulation, metabolic pathway, and other pathways. In particular, many ovule development genes and plant hormone-related genes showed significantly different methylation patterns in the two rice lines, and these differences may provide important clues for revealing the mechanism of female gametophyte abortion. [ABSTRACT FROM AUTHOR]

The female gametophyte is an important participant in the sexual reproduction of plants. The molecular mechanism of its development has received much attention in recent years. As important regulators of gene expression, miRNAs have been certified to play a significant role in many biological processes of plants, including sexual reproduction. In this study, to investigate the potential regulatory effects of miRNAs on rice female gametophyte abortion, we used the high-throughput sequencing method to compare the miRNA transcriptome in ovules of a high frequency female-sterile line (fsv1) and a rice wildtype line (Gui 99) during ovule development. As a result, 522 known miRNAs and 295 novel miRNAs were expressed in the developing ovule of rice, while 100 known miRNAs were significantly differentially expressed between these two rice lines during ovule development. Combining with gene expression information, a total of 627 coherent target genes of these differential expressed known miRNAs between fsvl and Gui 99 were identified. The functional analyses of these coherent target genes revealed that the coherent target genes of differential expressed known miRNAs between the two rice lines are involved in many biological pathways, such as protein degradation, auxin signal transduction, and transcription factor regulation. These results provide us with important clues to investigate the regulatory roles of miRNAs in rice female gametophyte abortion. [ABSTRACT FROM AUTHOR]