陆地棉AGPase基因家族的鉴定及表达分析

Identification and expression analysis of AGPase gene family in upland cotton(Gossypium hirsutum L.)

【目的】腺苷二磷酸葡萄糖焦磷酸化酶(adenosine diphosphate-glucose pyrophosphorylase,AGPase)是淀粉生物合成途径的限速酶,在植物“源”、“库”器官淀粉的合成与积累过程中扮演着重要角色,然而棉花中AGPase基因家族的系统研究工作尚未开展。【方法】基于已公布的陆地棉标准系TM-1基因组数据,利用生物信息学方法对陆地棉AGPase基因家族进行全基因组鉴定,并对该家族成员的理化性质、系统进化关系、基因结构、启动子区顺式作用元件进行分析。利用转录组数据和实时荧光定量聚合酶链式反应分析AGPase家族基因的组织表达特性和在非生物胁迫下的表达模式。【结果】在陆地棉基因组中,共鉴定到20个AGPase基因(GhAGP),不均匀地分布在16条染色体上。GhAGP基因包含12个大亚基基因和8个小亚基基因共2类,同一类GhAGP基因具有相似的保守基序和外显子-内含子结构。GhAGP基因启动子区含有多个与植物激素、非生物胁迫响应相关的顺式作用元件。组织表达分析结果显示,GhAGP基因具有不同的组织表达模式。非生物胁迫下的表达分析表明,多数GhAGP基因响应低温、高温、盐和干旱胁迫诱导表达,其中GhAGPL1和GhAGPL7参与棉花对多种逆境胁迫的响应。【结论】明确了陆地棉AGPase基因家族成员的分布特征、结构特征以及系统进化特征,初步揭示了该家族基因在棉花响应外界环境胁迫中的功能,可为棉花淀粉性状的遗传改良和抗逆育种提供重要的候选基因资源。

[Objective]Adenosine diphosphate-glucose pyrophosphorylase(AGPase)is the rate limiting enzyme in the starch biosynthesis pathway,which plays an important role in starch synthesis and accumulation of plant"source"and"sink"organs.However,the systematic study of AGPase gene family has not been carried out in cotton.[Method]In this study,the whole genome identification of AGPase gene family was carried out by bioinformatics based on the published genomic data of Gossypium hirsutum standard line TM-1.The physical and chemical properties,evolutionary relationship,gene structure,cis-acting elements in the promoter region were systematically analyzed.Transcriptomic data and real-time quantitative polymerase chain reaction(qRT-PCR)were used to analyze the expression patterns of AGPase family genes in different tissues and under various abiotic stresses.[Result]A total of 20 AGPase genes(GhAGP)were identified in G.hirsutum,and they were unevenly distributed on 16 chromosomes.There were 12 AGPase gene encoding AGPase large subunit and 8 AGPase gene encoding AGPase small subunit,and had similar conserved motifs and exon-intron structure in different groups.The promoter region of GhAGP had multiple cis-acting elements related to plant hormones and abiotic stress response.Expression analysis showed that GhAGP had different tissue expression patterns.The expression level analysis under abiotic stress showed that most GhAGP were induced by low temperature,high temperature,salt and drought stress,in which GhAGPL1 and GhAGPL7 were involved in the response to a variety of stresses in cotton.[Conclusion]The distribution,structural and phylogenetic characteristics of AGPase genes were clarified in G.hirsutum,and the function of AGPase gene family in response to external environmental stress was preliminarily revealed,which provide important candidate gene resources for genetic improvement of starch traits and stress resistance breeding in cotton.