Wei Zhenzhen, Li Yonghui, Ali Faiza, Wang Ye, Liu Jisheng, Yang Zuoren, Wang Zhi, Xing Yadi, Li Fuguang
Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou, 450001, China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Cell Biosci. 2022 Jul 12;12(1):107. doi: 10.1186/s13578-022-00840-4.
Histone deacetylation is one of the most important epigenetic modifications and plays diverse roles in plant development. However, the detailed functions and mechanisms of histone deacetylation in fiber development of cotton are still unclear. HDAC inhibitors (HDACi) have been commonly used to study the molecular mechanism underlying histone deacetylation or to facilitate disease therapy in humans through hindering the histone deacetylase catalytic activity. Trichostatin A (TSA)-the most widely used HDACi has been extensively employed to determine the role of histone deacetylation on different developmental stages of plants.
Through in vitro culture of ovules, we observed that exogenous application of TSA was able to inhibit the fiber initiation development. Subsequently, we performed a transcriptomic analysis to reveal the underlying mechanisms. The data showed that TSA treatment resulted in 4209 differentially expressed genes, which were mostly enriched in plant hormone signal transduction, phenylpropanoid biosynthesis, photosynthesis, and carbon metabolism pathways. The phytohormone signal transduction pathways harbor the most differentially expressed genes. Deeper studies showed that some genes promoting auxin, Gibberellic Acid (GA) signaling were down-regulated, while some genes facilitating Abscisic Acid (ABA) and inhibiting Jasmonic Acid (JA) signaling were up-regulated after the TSA treatments. Further analysis of plant hormone contents proved that TSA significantly promoted the accumulation of ABA, JA and GA.
Collectively, histone deacetylation can regulate some key genes involved in different phytohormone pathways, and consequently promoting the auxin, GA, and JA signaling, whereas repressing the ABA synthesis and signaling to improve the fiber cell initiation. Moreover, the genes associated with energy metabolism, phenylpropanoid, and glutathione metabolism were also regulated by histone deacetylation. The above results provided novel clues to illuminate the underlying mechanisms of epigenetic modifications as well as related different phytohormones in fiber cell differentiation, which is also very valuable for the molecular breeding of higher quality cotton.
组蛋白去乙酰化是最重要的表观遗传修饰之一，在植物发育中发挥着多种作用。然而，组蛋白去乙酰化在棉花纤维发育中的详细功能和机制仍不清楚。组蛋白去乙酰化酶抑制剂（HDACi）已被广泛用于研究组蛋白去乙酰化的分子机制，或通过抑制组蛋白去乙酰化酶的催化活性来促进人类疾病治疗。曲古抑菌素A（TSA）——最常用的HDACi，已被广泛用于确定组蛋白去乙酰化在植物不同发育阶段的作用。
通过胚珠的体外培养，我们观察到外源施加TSA能够抑制纤维起始发育。随后，我们进行了转录组分析以揭示其潜在机制。数据显示，TSA处理导致4209个差异表达基因，这些基因大多富集在植物激素信号转导、苯丙烷生物合成、光合作用和碳代谢途径中。植物激素信号转导途径中差异表达基因最多。深入研究表明，TSA处理后，一些促进生长素、赤霉素（GA）信号传导的基因下调，而一些促进脱落酸（ABA）和抑制茉莉酸（JA）信号传导的基因上调。对植物激素含量的进一步分析证明，TSA显著促进了ABA、JA和GA的积累。
总体而言，组蛋白去乙酰化可以调节参与不同植物激素途径的一些关键基因，从而促进生长素、GA和JA信号传导，同时抑制ABA合成和信号传导以促进纤维细胞起始。此外，与能量代谢、苯丙烷和谷胱甘肽代谢相关的基因也受组蛋白去乙酰化调节。上述结果为阐明表观遗传修饰以及相关不同植物激素在纤维细胞分化中的潜在机制提供了新线索，这对高品质棉花的分子育种也非常有价值。
