Table_2_Profiling of MicroRNAs Involved in Mepiquat Chloride-Mediated Inhibition of Internode Elongation in Cotton (Gossypium hirsutum L.) Seedlings.XLSX

Mepiquat chloride (MC) is the most important plant growth retardant that is widely used in cotton (Gossypium hirsutum 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(Mepiquat chloride, MC)是目前应用最为广泛的植物生长延缓剂，常用于陆地棉(Gossypium hirsutum L.)生产中，以抑制植株过度营养生长并优化株型。微小RNA(microRNAs, miRNAs)是调控植物生长发育的重要基因表达调控因子，但截至目前，缩节胺诱导的生长抑制过程中，miRNA介导的转录后调控机制仍不明晰。本研究针对棉花节间中响应缩节胺的miRNA动态表达谱展开系统分析，共计鉴定得到隶属于197个家族的508个已知miRNA，以及5个新发现的miRNA。其中，与对照组（0小时）相比，在缩节胺处理后48、72或96小时时，共有104个miRNA呈现显著差异表达，且其中绝大多数为高度保守的miRNA；差异表达miRNA的数量随处理后时间推移逐步增加。14个已知miRNA的表达持续受到抑制，而12个已知miRNA及1个新发现的miRNA的表达则持续被缩节胺诱导上调。研究采用实时荧光定量PCR(qRT-PCR)验证了9个差异表达miRNA的表达模式，并对已知及新发现miRNA的靶基因进行了预测，随后通过RNA连接酶介导的5'末端快速扩增(RLM-5′ RACE)技术验证了4个保守靶基因与6个新发现的靶基因。本研究揭示了miRNA在缩节胺诱导的节间伸长抑制过程中发挥关键调控作用，该成果有助于深化对缩节胺介导的生长抑制过程中转录后基因调控机制的认知，同时有望为矮化棉花的育种工作提供助力。