棉花PRR基因的功能分化与胁迫特异性表达分析OA

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 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 Gossypium 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_D1 1G001640 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.