高温胁迫下火龙果转录组及热激蛋白响应分析

Transcriptome analysis and HSP response of pitaya ( Selenicereus spp.) under heat stress

为探究火龙果(Selenicereus spp.)高温胁迫后基因表达变化,研究火龙果高温胁迫响应的关键基因,挖掘耐高温基因资源。本研究通过RNA-seq对25℃及40℃处理24 h的火龙果枝条进行测序,从系统生物学角度对差异表达基因进行分析。结果表明,火龙果在遭遇40℃胁迫24 h后,与25℃胁迫相比,枝条中有2 408个基因的表达发生显著变化,其中基因包括165个转录因子,占基因总量的6.7%;表达量上调2~587倍或者下调2~59倍。热激蛋白(HSP)在胁迫后表达量上调尤为显著,差异表达基因中上调程度最高的10个基因均为HSP,可能具有重要的胁迫耐受作用。通过qPCR对不同胁迫时间样品该10个HSP表达量检测发现,HSP18.2,HSP21,HSP22,HSP23.5,HSP23.6在胁迫5 h后表达量即上调至50倍以上,尤其是HSP21,在胁迫5 h后表达量即上调391倍,在10 h时表达量达到最高水平,上调589倍,响应速度高于其他基因。HSP的快速响应可能和火龙果的高温耐受性有关,HSP21可以作为火龙果高温胁迫的信号基因。

To investigate the changes in gene expression under high temperature stress of pitaya,we studied key genes that respond to such stress and screened heat-resistant gene resources.In this study,RNA-seq was used to sequence pitaya stems treated at 25℃and 40℃for 24 h,and differentially that under were analyzed from the perspective of systems biology.The results showed that after pitaya was subjected to 40℃for 24 h,and 2408 genes showed significant changes compared with expression relative to 25℃,including 165 transcription factors,accounting for 6.7%of the total number of genes;the expression level was up-regulated by 2 to 587 times or down-regulated by 2 to 59 times.Heat shock proteins(HSPs)were particularly up-regulated after stress,and the top 10 up-regulated genes in differentially expressed genes were all HSPs,which may have important stress tolerance effects.By qPCR detection of the expression levels of these 10 HSPs in samples at different stress time,it was found that HSP18.2,HSP21,HSP22,HSP 23.5 and HSP 23.6 were up-regulated by more than 50 times after stress for 5 h,especially HSP21,which was up-regulated by 391 times after stress for 5 h and reached the highest level after stress for 10 h with an up-regulation of 589 times.The rapid response of HSP may be related to the high temperature tolerance of pitaya.HSP 21 can be used as a signal gene for high temperature stress of pitaya.