玉米逆境胁迫响应基因ZmTPR1的表达和功能分析

Expression and Functional Analysis of Maize Stress Response Gene ZmTPR1

在前期干旱-复水处理玉米转录组测序基础上,发现了一个响应干旱胁迫的基因ZmTPR1(Tetratricopeptide repeat 1),对该基因进行生物信息学分析,并探究其在不同组织及逆境胁迫下的表达模式,利用CRISPR-Cas9技术敲除拟南芥中的同源基因AtTPR1,分析干旱胁迫条件下纯合突变体植株的表型和生理生化指标,初步探究该基因的功能,为培育抗旱玉米品种提供基因资源。结果表明,ZmTPR1基因位于玉米的第3号染色体,编码421个氨基酸,具有保守的卷曲螺旋结构域,可能参与玉米对植物激素、干旱等胁迫的响应。ZmTPR1基因在玉米各组织中均表达,在幼茎中的表达量最高;干旱、高温、盐和缺氮胁迫均可诱导ZmTPR1基因的表达,干旱胁迫后表达量上调最明显;干旱胁迫后ZmTPR1基因在抗旱玉米自交系郑36中的表达量均极显著高于敏旱玉米自交系B73。敲除AtTPR1基因后拟南芥抗旱能力下降,Attpr1突变体在干旱胁迫下生长受到严重抑制,叶片萎蔫甚至干死,同时相对含水量、叶绿素含量、净光合速率及过氧化物酶和超氧化物歧化酶活性极显著降低,丙二醛含量极显著升高。综合来看,ZmTPR1基因参与玉米对多种非生物胁迫的响应过程,并在响应干旱胁迫中发挥着重要的作用。

On the basis of previous transcriptome sequencing of maize under drought⁃rehydration treatment,ZmTPR1(tetratricopeptide repeat 1)was identified in response to drought stress.Bioinformatics analysis was conducted,and expression pattern was analyzed in different tissues and under different stresses.The homologous gene AtTPR1 in Arabidopsis thaliana was knocked out by CRISPR⁃Cas9 technology,the phenotype,physiological and biochemical indexes of homozygous mutant plants were analyzed under drought stress,and the function of this gene was preliminarily explored,which would provide genetic resources for breeding drought⁃resistant maize varieties.The results showed that ZmTPR1 gene was located on chromosome 3 of maize,encoding 421 amino acids,containing a conserved coiled coil domain,and might be involved in the response of maize to plant hormones,drought and so on.ZmTPR1 gene expressed in all tissues of maize,with the highest expression level in young stems.Drought,high temperature,salt and nitrogen deficiency stresses could induce the expression of ZmTPR1 gene,and the expression level of ZmTPR1 gene was most up⁃regulated after drought stress.The expression level of ZmTPR1 gene in drought-resistant maize inbred line Zheng 36 was significantly higher than that in drought-sensitive maize inbred line B73 after drought stress.Drought resistance of Arabidopsis thaliana decreased after AtTPR1 gene was knocked out,the growth of Attpr1 mutant was severely inhibited under drought stress,and the leaves were wilted or even dried out.At the same time,the relative water content,chlorophyll content,net photosynthetic rate,activities of peroxidase and superoxide dismutase significantly decreased,and the content of malondialdehyde significantly increased.In summary,ZmTPR1 gene is involved in the response of maize to various abiotic stresses,and plays an important role in drought stress.