College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.
Sichuan Yuliang Biotechnological Co. Ltd, Chengdu, 611130, Sichuan, China.
Mol Genet Genomics. 2019 Apr;294(2):501-517. doi: 10.1007/s00438-018-1524-4. Epub 2019 Jan 3.
MicroRNA164 (miR164) plays a key role in leaf and flower development, lateral root initiation, and stress responses. However, little is known about the regulatory roles of miR164 during seed development, particularly in maize. The aim of this study was to discover the developmental function of miR164 in maize seed. Small RNA sequencing (sRNA-seq) was performed at two key stages. The results indicated that miR164 was down-regulated during maize seed development. In addition, degradome library sequencing and transient expression assays identified the target genes for miR164. Two microRNA (miRNA) pairs, miR164-NAM, ATAF, and CUC32 (NAC32) and miR164-NAC40, were isolated. The developmental function of miR164 was determined by analyzing the differentially expressed genes (DEGs) between the wild-type and miR164 transgenic lines using RNA sequencing (RNA-seq) and by screening the DEGs related to NAC32 and NAC40 via co-expression and transient expression analysis. These results identified two beta-expansin genes, EXPB14 and EXPB15, which were located downstream of the NAC32 and NAC40 genes. This study revealed, for the first time, a miR164-dependent regulatory pathway, miR164-NAC32/NAC40-EXPB14/EXPB15, which participates in maize seed expansion. These findings highlight the significance of miR164 in maize seed development, and can be used to explore the role of miRNA in seed development.
miR164（微小 RNA164）在叶片和花发育、侧根起始和应激反应中发挥关键作用。然而，对于 miR164 在种子发育过程中的调控作用，特别是在玉米中，知之甚少。本研究旨在发现 miR164 在玉米种子发育中的功能。在两个关键阶段进行了小 RNA 测序（sRNA-seq）。结果表明，miR164 在玉米种子发育过程中下调。此外，降解组文库测序和瞬时表达实验鉴定了 miR164 的靶基因。分离出两对 miRNA（miRNA），miR164-NAM、ATAF 和 CUC32（NAC32）和 miR164-NAC40。通过 RNA 测序（RNA-seq）分析野生型和 miR164 转基因系之间差异表达基因（DEGs），并通过共表达和瞬时表达分析筛选与 NAC32 和 NAC40 相关的 DEGs，确定了 miR164 的发育功能。这些结果鉴定了两个 beta-扩张蛋白基因，EXPB14 和 EXPB15，它们位于 NAC32 和 NAC40 基因的下游。本研究首次揭示了 miR164 依赖的调控途径，miR164-NAC32/NAC40-EXPB14/EXPB15，参与了玉米种子的膨胀。这些发现强调了 miR164 在玉米种子发育中的重要性，并可用于探索 miRNA 在种子发育中的作用。
