Ma Xingli, Zhang Xingguo, Zhao Kunkun, Li Fapeng, Li Ke, Ning Longlong, He Jialin, Xin Zeyu, Yin Dongmei
College of Agronomy, Henan Agricultural University, Zhengzhou, China.
Front Plant Sci. 2018 Mar 20;9:349. doi: 10.3389/fpls.2018.00349. eCollection 2018.
Seed expansion in peanut is a complex biological process involving many gene regulatory pathways. MicroRNAs (miRNAs) play important regulatory roles in plant growth and development, but little is known about their functions during seed expansion, or how they contribute to seed expansion in different peanut lines. We examined seed miRNA expression patterns at 15 and 35 days after flowering (DAF) in two peanut eighth-generation recombinant inbred lines (RIL8); 8106, a medium-pod variety, and 8107, a super-pod variety. Using high-throughput sequencing, we identified 1,082 miRNAs in developing peanut seeds including 434 novel miRNAs. We identified 316 differentially expressed miRNAs by comparing expression levels between the two peanut lines. Interestingly, 24 miRNAs showed contrasting patterns of expression in the two RILs, and 149 miRNAs were expressed predominantly in only one RIL at 35 DAF. Also, potential target genes for some conserved and novel miRNAs were identified by degradome sequencing; target genes were predicted to be involved in auxin mediated signaling pathways and cell division. We validated the expression patterns of some representative miRNAs and 12 target genes by qPCR, and found negative correlations between the expression level of miRNAs and their targets. miR156e, miR159b, miR160a, miR164a, miR166b, miR168a, miR171n, miR172c-5p, and miR319d and their corresponding target genes may play key roles in seed expansion in peanut. The results of our study also provide novel insights into the dynamic changes in miRNAs that occur during peanut seed development, and increase our understanding of miRNA function in seed expansion.
花生种子膨大是一个复杂的生物学过程，涉及许多基因调控途径。微小RNA（miRNA）在植物生长发育中发挥重要调控作用，但关于它们在种子膨大过程中的功能，以及它们如何在不同花生品系的种子膨大过程中发挥作用，我们所知甚少。我们检测了两个花生八代重组自交系（RIL8）在开花后15天和35天（DAF）的种子miRNA表达模式；8106是一个中荚品种，8107是一个超级荚品种。通过高通量测序，我们在发育中的花生种子中鉴定出1082个miRNA，其中包括434个新的miRNA。通过比较两个花生品系的表达水平，我们鉴定出316个差异表达的miRNA。有趣的是，24个miRNA在两个RIL中表现出相反的表达模式，149个miRNA在35 DAF时仅在一个RIL中占主导地位表达。此外，通过降解组测序鉴定了一些保守和新的miRNA的潜在靶基因；预测靶基因参与生长素介导的信号通路和细胞分裂。我们通过qPCR验证了一些代表性miRNA和12个靶基因的表达模式，发现miRNA及其靶标的表达水平之间存在负相关。miR156e、miR159b、miR160a、miR164a、miR166b、miR168a、miR171n、miR172c-5p和miR319d及其相应的靶基因可能在花生种子膨大过程中起关键作用。我们的研究结果还为花生种子发育过程中miRNA的动态变化提供了新的见解，并增加了我们对miRNA在种子膨大过程中功能的理解。
