马尾松HDR基因克隆及其对旱与盐胁迫的响应

干旱和土地盐渍化是制约林业可持续发展的重要因素,植物在遭受生物或非生物胁迫时,会在叶片释放萜类等挥发性物质。1-羟基-2-甲基-2-(E)-丁烯基-4-焦磷酸还原酶(HDR)是MEP途径的末端活性酶,具有提供前体萜类物质和主要限速作用。为探究马尾松HDR基因是否参与干旱和盐胁迫条件下的胁迫响应,该研究克隆了马尾松HDR基因开放阅读框,并初步分析了其生物信息、组织特异性表达水平和初步功能。结果表明:(1)PmHDR基因编码区长度为1 458 bp,编码485个氨基酸,其编码蛋白包含LytB/IspH基因超家族的核心序列和PLN02821多功能结构域,属于HDR家族。(2)PmHDR密码子使用偏好性较弱,偏好使用A/U结尾的密码子,烟草、拟南芥与酿酒酵母更适合作为其异源表达受体。(3)qRT-PCR结果显示,PmHDR基因在马尾松老叶中表达量最高,其次为幼叶、幼茎和老茎,在根中表达量最低。(4)构建基因表达载体pBI121-PmHDR并转化拟南芥,转基因拟南芥对干旱和盐胁迫表现出更强的抗逆性。以上研究结果表明PmHDR参与了植物干旱和盐胁迫的响应和调节,并为马尾松抗逆育种提供了一定的理论支持。

Cloning of HDR gene in Pinus massoniana and Cloningits response to drought and salt stresses

Drought and land salinization are inhibiting factors for the sustainable development of forestry, and the plants will release volatile substances such as terpenoids during biological or non-biological stress. The 1-hydroxy-2-methyl-2-(E)-buteny-4-pyrophosphate reductase is the terminal active enzyme of the MEP pathway, which provides precursor terpenoids and has the main rate-limiting effect. In order to investigate whether HDR gene of Pinus massoniana is involved in stress response under drought and salt stress, the open reading frame of PmHDR gene was cloned, and bioinformation, tissue specific expression and preliminary function were analyzed. The results were as follows:(1)The coding region length of PmHDR gene is 1 458 bp, encoding 485 amino acids, and its encoded protein contains the core sequence of LytB/IspH gene superfamily and PLN02821 multifunctional structural domain, which belongs to the HDR family.(2)The PmHDR codon use preference was weak, with a preference for codons ending in A/U. Nicotiana tabacum, Arabidopsis thaliana and Saccharomyces cerevisiae were more suitable as its heterologous expression receptors.(3)Results of qRT-PCR showed that the PmHDR gene was most highly expressed in old needles of Pinus massoniana, followed by young needles, young stem and old stem and least expressed in root.(4)The gene expression vector pBI121-PmHDR was constructed and transformed into Arabidopsis thaliana. The transgenic A. thaliana showed greater resistance to drought and salt stress. These results indicate that PmHDR is involved in plant response and regulation to drought and salt stress, and provide some theoretical supports for Pinus massoniana stress-resistance breeding.