Wang Li, Yin Ying, Jing Xiuxiu, Wang Menglei, Zhao Miao, Yu Juanjuan, Qiu Zongbo, Li Yong-Fang
College of Life Sciences, Henan Normal University, Xinxiang, China.
Henan International Joint Laboratory of Agricultural Microbial Ecology and Technology, Henan Normal University, Xinxiang, China.
Front Plant Sci. 2021 Feb 24;12:643213. doi: 10.3389/fpls.2021.643213. eCollection 2021.
Mepiquat chloride (MC) is the most important plant growth retardant that is widely used in cotton ( L.) production to suppress excessive vegetative growth and improve plant architecture. MicroRNAs (miRNAs) are important gene expression regulators that control plant growth and development. However, miRNA-mediated post-transcriptional regulation in MC-induced growth inhibition remains unclear. In this study, the dynamic expression profiles of miRNAs responsive to MC in cotton internodes were investigated. A total of 508 known miRNAs belonging to 197 families and five novel miRNAs were identified. Among them, 104 miRNAs were differentially expressed at 48, 72, or 96 h post MC treatment compared with the control (0 h); majority of them were highly conserved miRNAs. The number of differentially expressed miRNAs increased with time after treatment. The expression of 14 known miRNAs was continuously suppressed, whereas 12 known miRNAs and one novel miRNA were continuously induced by MC. The expression patterns of the nine differentially expressed miRNAs were verified using qRT-PCR. The targets of the known and novel miRNAs were predicted. Four conserved and six novel targets were validated using the RLM-5' RACE assay. This study revealed that miRNAs play crucial regulatory roles in the MC-induced inhibition of internode elongation. It can improve our understanding of post-transcriptional gene regulation in MC-mediated growth inhibition and could potentially facilitate the breeding of dwarf cotton.
缩节胺（MC）是最重要的植物生长延缓剂，广泛用于棉花生产中，以抑制过度的营养生长并改善植株形态。微小RNA（miRNA）是控制植物生长发育的重要基因表达调节因子。然而，miRNA介导的转录后调控在MC诱导的生长抑制中的作用仍不清楚。在本研究中，研究了棉花节间中对MC响应的miRNA的动态表达谱。共鉴定出属于197个家族的508个已知miRNA和5个新miRNA。其中，与对照（0小时）相比，104个miRNA在MC处理后48、72或96小时差异表达；它们中的大多数是高度保守的miRNA。差异表达的miRNA数量随着处理后的时间增加。14个已知miRNA的表达持续受到抑制，而12个已知miRNA和1个新miRNA被MC持续诱导。使用qRT-PCR验证了9个差异表达miRNA的表达模式。预测了已知和新miRNA的靶标。使用RLM-5'RACE分析验证了4个保守靶标和6个新靶标。本研究表明，miRNA在MC诱导的节间伸长抑制中起关键调节作用。它可以增进我们对MC介导的生长抑制中转录后基因调控的理解，并可能有助于矮化棉花的育种。
