Comparison of miRNAs and Their Targets in Seed Development between Two Maize Inbred Lines by High-Throughput Sequencing and Degradome Analysis

MicroRNAs (miRNAs) play an important role in plant growth, development, and response to environment. For identifying and comparing miRNAs and their targets in seed development between two maize inbred lines (i.e. PH6WC and PH4CV), two sRNAs and two degradome libraries were constructed. Through high-throughput sequencing and miRNA identification, 55 conserved and 24 novel unique miRNA sequences were identified in two sRNA libraries; moreover, through degradome sequencing and analysis, 137 target transcripts corresponding to 38 unique miRNA sequences were identified in two degradome libraries. Subsequently, 16 significantly differentially expressed miRNA sequences were verified by qRT-PCR, in which 9 verified sequences obviously target 30 transcripts mainly involved with regulation in flowering and development in embryo. Therefore, the results suggested that some miRNAs (e.g. miR156, miR171, miR396 and miR444) related reproductive development might differentially express in seed development between the PH6WC and PH4CV maize inbred lines in this present study.

微小RNA（microRNAs，miRNAs）在植物生长、发育及环境响应过程中发挥重要调控功能。为鉴定并比较两个玉米自交系（PH6WC与PH4CV）种子发育阶段的miRNA及其靶标，本研究构建了两个小RNA（small RNAs，sRNAs）文库与两个降解组（degradome）文库。通过高通量测序与miRNA鉴定分析，在两个sRNA文库中共鉴定到55条保守型独特miRNA序列与24条新型独特miRNA序列；此外，通过降解组测序与分析，在两个降解组文库中鉴定到对应38条独特miRNA序列的137个靶标转录本。随后，通过qRT-PCR验证了16条显著差异表达的miRNA序列，其中9条经验证的miRNA可靶向30个主要参与开花调控与胚胎发育的转录本。本研究结果表明，部分与生殖发育相关的miRNA（如miR156、miR171、miR396及miR444）在PH6WC与PH4CV玉米自交系的种子发育过程中存在差异表达。