辣椒PP2C家族基因鉴定与响应低温胁迫的表达分析

Identification and expression analysis of PP2C family genes in pepper in response to low temperature stress

对辣椒PP2C基因家族成员进行全基因组鉴定和特征分析,并研究CaPP2Cs基因在低温胁迫下的表达模式,结果表明:在辣椒参考基因组共系统鉴定出99个CaPP2Cs基因家族成员,并不均匀地分布在12条染色体上,CaPP2Cs基因编码的氨基酸数介于99~1 572 aa,分子量介于10.94~178.40 Da,等电点介于4.08~9.51。系统进化树分析可将辣椒和拟南芥的PP2C基因分为13个亚族,每个亚族均含有辣椒PP2C基因,基因结构分析表明CaPP2Cs基因的外显子数量介于1~18;在CaPP2Cs基因的启动子中发现许多与光、低温和激素响应有关的顺式作用元件。转录组数据分析表明,CaPP2C31基因在叶片中的表达量显著高于其他基因,CaPP2C16则特异性地表达于授粉后50 d的胎座中。低温处理24 h时,CaPP2C97和CaPP2C3在叶片中呈现显著的下调表达;低温处理1 h时,CaPP2C36、CaPP2C5、CaPP2C53、CaPP2C43、CaPP2C99等基因在根中明显上调,CaPP2C19、CaPP2C23、CaPP2C44、CaPP2C95则显著下调,表明CaPP2Cs可能在辣椒响应低温胁迫中发挥作用。

In this study,we performed genome-wide identification and characterization of pepper PP2C gene family members and analyzed the expression pattern of CaPP2Cs genes under low temperature stress.A total of 99 CaPP2Cs gene family members were systematically identified in the pepper reference genome,and CaPP2Cs genes were unevenly distributed on 12 chromosomes.The number of amino acids encoded by CaPP2Cs genes ranged from 99 to 1572 aa,the molecular weight ranged from 10.94 to 178.40 Da,and the isoelectric point ranged from 4.08 to 9.51.The phylogenetic tree analysis divided the PP2C genes of pepper and Arabidopsis into 13 subfamilies,each containing pepper PP2C genes.The gene structure analysis showed that the number of exons of CaPP2Cs genes ranged from 1 to 18,and many cis-acting elements related to light.Low temperature and hormone response were found in the promoters of CaPP2Cs genes.Analysis of transcriptome data showed that CaPP2C31 gene was significantly more expressed in leaves than other genes,and CaPP2C16 was specifically expressed in the placenta 50 days after pollination.In addition,CaPP2C97 and CaPP2C3 showed significant down-regulated expression in leaves at 24 h of low temperature treatment,CaPP2C36,CaPP2C5,CaPP2C53,CaPP2C43,and CaPP2C99 genes were significantly up-regulated at 1 h.CaPP2C19,CaPP2C23,CaPP2C44,and CaPP2C95 were significantly down-regulated,indicating that CaPP2Cs might play a role in pepper response to low temperature stress.