Mechanism of the Mixture of Abscisic Acid and Thidiazuron in Regulating Cotton Leaf Abscission

Morphological analysis and RNA-seq were conducted to profile the differentially expressed genes (DEGs) at different time points after treatment with a mixture of ABA and TDZ (AT), a mixture of TDZ and diuron (TD), ABA (A), TDZ (T), or water (W). A total of 2805 DEGs were detected after treatment with A, 18 849 DEGs after treatment with T, 29 822 DEGs after treatment with AT, and 26 446 DEGs after treatment with TD. GO and KEGG analyses revealed the enrichment of functional categories, including plant hormone signal transduction and metabolic pathways, after AT treatment. Ethylene-related genes (ACO3 and ACS) and cytokinin oxidase/dehydrogenase (CKX) were upregulated. Cytokinin response regulatory factors (ARRs) were downregulated, and the cytokinin content was decreased. Gibberellin-related genes (GIDs) were downregulated, and jasmonic-acid-related genes (JAZ10) were upregulated. The results showed that the interaction between ethylene and CTK regulated cotton leaf defoliation after AT treatment. Significantly, gibberellin and jasmonic acid also played a role in cotton leaf defoliation. The results of this study lay a foundation for further exploration of the function of ABA and TDZ in regulating cotton defoliation.

本研究通过形态学分析与RNA测序（RNA-seq），对脱落酸（ABA）与噻苯隆（TDZ）混合液（AT组）、噻苯隆与敌草隆（diuron）混合液（TD组）、脱落酸（A组）、噻苯隆（T组）及清水处理（W组）后不同时间点的差异表达基因（DEGs）进行了表达谱分析。经检测，A组处理后共鉴定出2805个DEGs，T组处理后为18849个，AT组处理后为29822个，TD组处理后为26446个。基因本体（GO）与京都基因与基因组百科全书（KEGG）富集分析显示，AT组处理后，植物激素信号转导与代谢通路等功能类别显著富集。乙烯相关基因（1-氨基环丙烷-1-羧酸氧化酶3（ACO3）与氨基环丙烷羧酸合酶（ACS））及细胞分裂素氧化酶/脱氢酶（CKX）呈上调表达；细胞分裂素响应调节因子（ARRs）呈下调表达，且细胞分裂素含量降低。赤霉素相关基因（GIDs）下调表达，茉莉酸ZIM结构域蛋白10（JAZ10）上调表达。研究结果表明，AT处理后，乙烯与细胞分裂素（CTK）的互作调控了棉花叶片脱叶过程；尤为重要的是，赤霉素与茉莉酸同样参与了棉花叶片脱叶进程。本研究结果为进一步探究脱落酸与噻苯隆调控棉花脱叶的功能机制奠定了理论基础。