棉花PRR基因的功能分化与胁迫特异性表达分析

Functional divergence and stress-specific expressionanalysis of Gossypium PRR genes

关键词:  棉花, PRR基因, 逆境适应, 纤维发育, 棉花育种

Key words:  cotton, PRR genes, stress adaptation, fiber development, cotton breeding

摘要:

伪响应调节因子(pseudo-response regulators,PRRs)是调节植物昼夜节律与开花期的关键因子,在多种植物中的功能已得到广泛验证。然而,该基因家族在棉花物种中的进化路径与生物学功能尚不清晰。为系统解析棉花PRR基因家族的进化特征及其潜在功能,该文整合BLASTP、Pfam及NCBI数据库,对4类棉花物种,即亚洲棉(Gossypium arboreum)、雷蒙德氏棉(G. raimondii)、陆地棉(G. hirsutum)、海岛棉(G. barbadense)以及拟南芥(Arabidopsis thaliana)中鉴定得到的32个PRR基因进行了进化分析与表达模式研究。结果表明:(1)PRR基因分为3个进化上保守的亚类(A、B、C),其起源早于单子叶与双子叶植物的分化; 所有成员均含CCT结构域,多数具有CCT-Response_reg双结构域。(2)PRR基因的启动子区域在不同物种间存在显著异质性,亚洲棉中以胁迫及光响应元件(如ABRE、ACE)为主,而陆地棉与海岛棉中的启动子则扩展至防御机制、激素响应和光信号传导(如MYB、G14K)。(3)PRR基因具有组织特异性表达和胁迫响应分化,其中Ghir_D12G025960在纤维和胚珠中富集,Ghir_D11G001640表现为冷诱导但受盐/干旱胁迫抑制,Ghir_D12G025960在热胁迫下呈现先抑制后恢复的独特表达动态。该研究系统解析了棉花PRR基因的结构多样性、进化关系及其在发育与胁迫响应中的功能分化,为棉花生物钟调控机制研究与抗逆育种提供了重要基因资源与理论依据。

Abstract:

Pseudo-response regulators(PRRs)are key regulators of plant circadian rhythms and flowering time, with their functions having been extensively validated across a wide range of plant species. However, the evolutionary trajectory and biological roles of this gene family in cotton remain poorly understood. To systematically dissect the evolutionary characteristics and potential functions of the PRR gene family in cotton, this study integrated data from BLASTP, Pfam, and NCBI databases to perform evolutionary analyses and expression pattern investigations on 32 PRR genes identified from four cotton species—Gossypium arboreum, G. raimondii, G. hirsutum, G. barbadense —as well as the model plant Arabidopsis thaliana. The results were as follows:(1)The PRR genes were clustered into three evolutionarily conserved subclasses(A, B, and C), whose origin predated the divergence of monocotyledonous and dicotyledonous plants. All PRR members contained the CCT domain, while the majority possessed a dual CCT-Response_reg domain architecture.(2)Significant heterogeneity was observed in the promoter regions of PRR genes among different cotton species, those in G. arboreum were dominated by stress- and light-responsive elements(e.g., ABRE, ACE), whereas promoters in G. hirsutum and G. barbadense had expanded to include elements associated with defense mechanisms, hormone signaling, and light signal transduction(e.g., MYB, G14K).(3)PRR genes exhibited tissue-specific expression patterns and divergent stress response profiles. Specifically, Ghir_D12G025960 was highly enriched in fibers and ovules; Ghir_D11G001640 was induced by cold stress but repressed under salt or drought conditions; and Ghir_D12G025960 displayed a unique expression dynamic of initial inhibition followed by recovery under heat stress. This study comprehensively characterizes the structural diversity, evolutionary relationships, and functional differentiation of cotton PRR genes in development and stress responses. These findings provide valuable genetic resources and a theoretical framework for future research on the cotton circadian clock regulatory network and the genetic improvement of stress tolerance in cotton breeding.