胡萝卜抗坏血酸过氧化物酶基因的分离及其对非生物胁迫的响应

[目的]抗坏血酸过氧化物酶(APX)利用抗坏血酸作为电子供体,清除植物中的过氧化物,在植物应对非生物胁迫中起重要作用。本文目的是研究胡萝卜DcAPX基因在抵御逆境胁迫过程中的响应情况。[方法]以胡萝卜‘黑田五寸’为研究材料,克隆获得胡萝卜DcAPX基因(GenBank登录号为KR364573),对该基因进行序列分析,并研究其主要非生物胁迫(高温、低温、干旱和盐胁迫)下的基因表达情况。[结果]序列分析表明,胡萝卜DcAPX基因全长753个碱基,编码250个氨基酸,预估其蛋白质相对分子质量为27.76×103,pI值5.65。进化分析表明,胡萝卜DcAPX在进化关系上与同属伞形科的短果茴芹同源性最高。空间结构分析表明,胡萝卜DcAPX的氨基酸二级结构由38.40%的α-螺旋、10.40%的延伸主链和51.20%的随机卷曲构成。胡萝卜DcAPX的氨基酸三级结构由10个α-螺旋和4个β-折叠构成。实时荧光定量PCR结果显示,胡萝卜‘黑田五寸’中DcAPX基因表达具有组织特异性,在叶中表达量最高。[结论]胡萝卜中DcAPX基因可以响应多种非生物逆境胁迫,在胡萝卜非生物逆境胁迫调控过程中起着重要作用。
[Objectives]Ascorbate peroxidase(APX)removes excess plant peroxides by using an electron donor from ascorbic acid,which is an essential mechanism in response to abiotic stress. The aim of the paper is to study the response of DcAPX gene in the process of resisitance to abiotic stress. [Methods]The DcAPX gene was cloned from carrot variety‘Kurodagosun’. Expression profiles under high and low temperature,drought,and salinity treatments were performed to further understand the roles of the gene in response to abiotic stress in carrot. The gene was submitted to GenBank and the accession number is KR364573. [Results]Sequence analysis indicated that the length of DcAPX gene was 753 bp,which encoded 250 amino acids. It is predicted that the relative molecular mass of its protein was 27.76×103,and pI was 5.65. Amino acid sequence comparison showed that the evolutionary relationship of DcAPX from carrot was close to Pimpinella brachycarpa,which both belong to the Apiaceae family. Structure analysis showed that DcAPX was made up of 38.40% alpha helix,10.40% extended strand,and 51.20% random coil. Analysis on three-dimension structure implied that the enzyme was composed of 10 alpha helixes and 4 beta sheets. Quantitative real-time PCR analysis demonstrated that carrot DcAPX gene was tissue-specific,and had the highest expression level in the leaf. [Conclusions]DcAPX gene was significantly induced by abiotic stress,and the gene may play important roles in resistance against abiotic stress