干旱胁迫显著影响生长,发展,和棉花产量,触发多个基因的反应。其中,抗坏血酸过氧化物酶(APX)是植物体内活性氧代谢的重要抗氧化酶之一,APX增强了植物抗氧化的能力,从而提高植物的抗逆性。因此,增强细胞中APX的活性对提高植物抗逆性至关重要。先前的研究已经在抗旱(KK1543)和干旱敏感(XLZ26)植物中分离出干旱胁迫(GhAPX7)下差异表达的蛋白质。因此,本研究分析了GhAPX7在不同棉花组织中的表达模式,以验证GhAPX7的抗旱功能并探索其调控途径。GhAPX7在棉花叶片中的表达量最高,在干旱胁迫下显著增加,表明GhAPX7对于提高棉花的抗氧化能力和酶活性至关重要。GhAPX7沉默间接影响干旱胁迫下抗旱和干旱敏感植物的明显叶片黄化和枯萎。与对照相比,沉默植物的丙二醛(MDA)含量显着增加,叶绿素和脯氨酸含量以及APX酶活性普遍降低。这表明GhAPX7可能通过影响MDA含量来提高抗旱性,叶绿素,脯氨酸,和APX酶活性通过增加表达水平。转录组分析表明,对照和处理组之间与干旱相关的差异表达基因丰富了植物激素信号转导,MAPK信号,和植物-病原体相互作用途径。因此,GhAPX7的表达降低显著影响这三个通路中基因的表达水平,降低植物的抗旱性。本研究揭示了GhAPX7的分子机制及其在抗旱性中的作用,为进一步研究棉花响应干旱胁迫的分子机制奠定了基础。
Drought stress significantly affects the growth, development, and yield of cotton, triggering the response of multiple genes. Among them, ascorbate peroxidase (APX) is one of the important antioxidant enzymes in the metabolism of reactive oxygen species in plants, and APX enhances the ability of plants to resist oxidation, thus increasing plant stress tolerance. Therefore, enhancing the activity of APX in cells is crucial to improving plant stress resistance. Previous studies have isolated differentially expressed proteins under drought stress (GhAPX7) in drought-resistant (KK1543) and drought-sensitive (XLZ26) plants. Thus, this study analyzed the expression patterns of GhAPX7 in different cotton tissues to verify the drought resistance function of GhAPX7 and explore its regulatory pathways. GhAPX7 had the highest expression in cotton leaves, which significantly increased under drought stress, suggesting that GhAPX7 is essential for improving antioxidant capacity and enzyme activities in cotton. GhAPX7 silencing indirectly affects pronounced leaf yellowing and wilting in drought-resistant and drought-sensitive plants under drought stress. Malondialdehyde (MDA) content was significantly increased and chlorophyll and proline content and APX enzyme activity were generally decreased in silenced plants compared to the control. This result indicates that GhAPX7 may improve drought resistance by influencing the contents of MDA, chlorophyll, proline, and APX enzyme activity through increased expression levels. Transcriptome analysis revealed that the drought-related differentially expressed genes between the control and treated groups enriched plant hormone signal transduction, MAPK signaling, and plant-pathogen interaction pathways. Therefore, the decreased expression of GhAPX7 significantly affects the expression levels of genes in these three pathways, reducing drought resistance in plants. This study provides insights into the molecular mechanisms of GhAPX7 and its role in drought resistance and lays a foundation for further research on the molecular mechanisms of response to drought stress in cotton.