紫花苜蓿MsHSP17.7基因的克隆及功能分析

Cloning and Functional Analysis of MsHSP17.7 Gene from Alfalfa

热激蛋白是一类普遍参与抗逆的保护性蛋白,在植物生长发育及逆境调控中起重要作用。为了解紫花苜蓿(Medicago sativa L.)热激蛋白基因特性及功能,本研究通过同源克隆法获得热激蛋白基因MsHSP17.7,该基因包含477bp开放阅读框,编码158个氨基酸,蛋白分子量为17.67kDa。序列比对发现MsHSP17.7与截形苜蓿(Medicago truncatula)和豌豆(Pisum sativum)中的2个小分子热激蛋白同源性较高,相似度分别是93.38%,83.13%。组织差异性表达显示,MsHSP17.7在茎中表达最多,叶和花次之,在根中最少;实时定量PCR分析显示,MsHSP17.7受高温、高盐诱导表达,在过氧化诱导下表达量变化不明显。对T3代转基因拟南芥(Arabidopsis thaliana)实时定量PCR分析显示,该基因在高盐和过氧化胁迫下均能大量表达,结果表明MsHSP17.7基因可能参与了高盐与过氧化逆境下的胁迫应激调控。

Heat shock protein（HSP）is a kind of ubiquitous protective protein that plays an important role in plant development and stress adaption.In order to learn more about expression characteristics and function of small HSP gene,MsHSP17.7gene was cloned from alfalfa（Medicago sativa L.）through homology-based cloning.MsHSP17.7contains an open reading frame of 477-bp encoding aprotein of 17.67-kDa.The amino acid sequence shares 93.38% and 83.13%identity with sHSPs in Medicagotruncatula and in Pisum sativum.Quantitative RT-PCR results showed that the maximum mRNA expression of MsHSP17.7was in stems,followed by leaves and flowers,and the least was in root.MsHSP17.7was induced by high temperature and high salinity stress,but the expression did not chang obviously under peroxide stress.Then the quantitative RT-PCR indicated that MsHSP17.7was abundantly expressed under high salinity stress and peroxide stress in T3 transgenic Arabidopsis.In summary,results implied that MsHSP17.7might involve in the regulation of high salinity stress and peroxide stress response.