Abstract: Evolution analysis and stress response of RCAR gene family in wheat is helpful for understanding the regulatory mechanism of RCAR genes in stress resistance. Based on conserved domains, 27 RCARs were identified from the whole wheat genome. They distributed on the chromosomes except chromosomes 5 and 6. The wheat RACRs were classified into 6 groups based on their evolutionary relationship, and 12 TaRCARs from GroupA and GroupB exhibited rapid evolution, with the ω values of 0349 and 0321, respectively. For GroupA, 3 sites (P>099) were identified to experience positive selection. 4 main cisacting elements were identified in the promoters of TaRCARs, which involved in abiotic stress response, light response, hormone response and plant growth and development. RNAseq expression profiles showed that TaRCAR1, TaRCAR2, TaRCAR4 and TaRCAR7 were constitutively expressed, whereas others showed tissue specificity. The RCARs showed different response patterns under drought and heat stress, the expressions of TaRCAR3 and TaRCAR6 increased within 12 h after heat stress, TaRCAR1, TaRCAR3 and TaRCAR6 increased in both drought stress and heat stress within 6 h, expression of TaRCAR5 was upregulated only after drought stress, and expression of TaRCAR7 was downregulated only under heat stress.

Key words: wheat, RCAR gene family, positive selection, evolution analysis, stress response

摘要： 研究小麦RCAR基因家族的进化与逆境响应，有助于阐明RCAR基因抵御逆境胁迫的调控机制。根据保守结构域在小麦基因组中鉴定出27个RCARs，除了第5和6同源群外，其余同源群均有分布。根据进化关系可分为6个亚组；GroupA和GroupB中12个TaRCARs均检测到快速进化，ω值分别为0349和0321，GroupA中3个位点经历了正选择，后验概率P＞099；TaRCARs启动子顺式元件主要有4类，分别参与非生物胁迫应答、光响应、激素响应和生长发育过程。比较RNAseq表达谱发现TaRCAR1、TaRCAR2、TaRCAR4和TaRCAR7是组成型表达，其余基因的表达具有组织特异性；在干旱和热胁迫下RCARs响应模式不同，除TaRCAR3和TaRCAR6在热胁迫后12 h内表达提高外，TaRCAR1、TaRCAR3和TaRCAR6均在干旱胁迫和热胁迫后6 h内提高，TaRCAR5在干旱胁迫后表达上调，TaRCAR7在热胁迫时表达下调。

关键词: 小麦, RCAR基因家族, 正选择, 进化分析, 逆境响应