Investigation of Maize miRNA Involved in Developing-ear Heterosis
Heterosis has been utilized widely in maize breeding; it plays an important role in increasing yield, improving quality and enhancing stresses resistance. However, the molecular mechanism of heterosis is far from clear. MicroRNAs (miRNAs) act as key regulating factors of gene expression in post-transcriptional level. To investigate whether miRNA-dependent gene regulation is responsible for heterosis during maize ear development, we performed an illumine miRNA deep-sequencing on the most widely-planted elite hybrid Zhengdan 958 and its parental inbred lines (Chang 7-2 and Zheng 58) in China. The ear samples at the developmental stages of inflorescence meristem (IM) producing spikelet pair meristems (SPM), resulting in spikelet meristems (SMs), and floral meristems (FM) were collected for RNA library construction. As a result, 81 conserved miRNAs belonging to 16 miRNA families were identified which were non-additively expressed. At the three stages, 80.30%, 56.06%, and 48.10% of these non-additively expressed miRNAs were repressed ever dominantly or over-dominantly. A total of 82 target transcripts from 42 genes of conserved miRNAs among Zhengdan 958 and its parents were detected via whole genome degradome sequencing. Additionally, eight novel maize miRNAs belonging to seven miRNA families were identified using stringent criteria. Global repression of miRNAs in hybrid ears at the early stage might lead to the up-regulated expressing of their target genes. Moreover, the in-step de-repression of given miRNA family members may be the reason of enhanced repression of their target genes. These results revealed, at least in part, the involvement of maize miRNAs in hybrids leads to higher ear developing vigor compared with its parental lines.
国家科技期刊平台
NSTL
万方数据
维普
