Institute of Cotton, Hebei Academy of Agriculture and Forestry Sciences, Key Laboratory of Cotton Biology and Genetic Breeding in Huanghuaihai Semiarid Area, Ministry of Agriculture and Rural Affairs, Shijiazhuang, P.R. China.
College of Food Science and Biology, Hebei University of Science and Technology, Shijiazhuang, P.R. China.
BMC Plant Biol. 2024 Mar 12;24(1):182. doi: 10.1186/s12870-024-04862-7.
Cotton boll shedding is one of the main factors adversely affecting the cotton yield. During the cotton plant growth period, low light conditions can cause cotton bolls to fall off prematurely. In this study, we clarified the regulatory effects of low light intensity on cotton boll abscission by comprehensively analyzing the transcriptome and metabolome.
When the fruiting branch leaves were shaded after pollination, all of the cotton bolls fell off within 5 days. Additionally, HO accumulated during the formation of the abscission zone. Moreover, 10,172 differentially expressed genes (DEGs) and 81 differentially accumulated metabolites (DAMs) were identified. A KEGG pathway enrichment analysis revealed that the identified DEGs and DAMs were associated with plant hormone signal transduction and flavonoid biosynthesis pathways. The results of the transcriptome analysis suggested that the expression of ethylene (ETH) and abscisic acid (ABA) signaling-related genes was induced, which was in contrast to the decrease in the expression of most of the IAA signaling-related genes. A combined transcriptomics and metabolomics analysis revealed that flavonoids may help regulate plant organ abscission. A weighted gene co-expression network analysis detected two gene modules significantly related to abscission. The genes in these modules were mainly related to exosome, flavonoid biosynthesis, ubiquitin-mediated proteolysis, plant hormone signal transduction, photosynthesis, and cytoskeleton proteins. Furthermore, TIP1;1, UGT71C4, KMD3, TRFL6, REV, and FRA1 were identified as the hub genes in these two modules.
In this study, we elucidated the mechanisms underlying cotton boll abscission induced by shading on the basis of comprehensive transcriptomics and metabolomics analyses of the boll abscission process. The study findings have clarified the molecular basis of cotton boll abscission under low light intensity, and suggested that HO, phytohormone, and flavonoid have the potential to affect the shedding process of cotton bolls under low light stress.
棉花脱落是影响棉花产量的主要因素之一。在棉花植株生长期间，光照条件不足会导致棉铃过早脱落。本研究通过综合分析转录组和代谢组，阐明了低光强对棉花脱落的调控作用。
授粉后对结果枝叶片遮光，所有棉铃均在 5 天内脱落。此外，HO 在脱落区形成过程中积累。此外，鉴定出 10172 个差异表达基因（DEGs）和 81 个差异积累代谢物（DAMs）。KEGG 途径富集分析表明，鉴定出的 DEGs 和 DAMs 与植物激素信号转导和黄酮类生物合成途径有关。转录组分析结果表明，乙烯（ETH）和脱落酸（ABA）信号相关基因的表达被诱导，而大多数 IAA 信号相关基因的表达则下降。转录组和代谢组联合分析表明，类黄酮可能有助于调节植物器官脱落。加权基因共表达网络分析检测到两个与脱落显著相关的基因模块。这些模块中的基因主要与外体、类黄酮生物合成、泛素介导的蛋白水解、植物激素信号转导、光合作用和细胞骨架蛋白有关。此外，在这两个模块中鉴定出 TIP1;1、UGT71C4、KMD3、TRFL6、REV 和 FRA1 为枢纽基因。
本研究基于对棉铃脱落过程的综合转录组和代谢组分析，阐明了遮荫诱导棉铃脱落的机制。研究结果阐明了低光强下棉花脱落的分子基础，并表明 HO、植物激素和类黄酮有可能影响低光胁迫下棉花脱落的过程。
