玉米大斑病菌交配型基因克隆及生物信息学分析

摘要

以真菌毒素与分子植物病理学实验室前期分离、鉴定并保存的玉米大斑病菌菌株F 1-40（A交配型菌株）、01-23（a交配型菌株）为试验材料，利用候选基因法，通过PCR扩增和Genome Walking 技术，对A交配型菌株和a 交配型菌株的MAT基因进行同源片段扩增，从而获得基因全长及其侧翼序列，进一步利用生物信息学方法对扩增得到的MAT基因全长进行保守结构域分析，利用玉米大斑病菌基因组数据库的Blast序列比对软件将MAT1基因和MAT2基因的侧翼序列进行比对。研究结果表明，在不同交配型的玉米大斑病菌中，A交配型的菌株中含有A交配型基因MAT1，a交配型菌株中含有a交配型基因MAT2。2个基因均含有1个内含子，其中MAT1基因编码包括1个完整的MAT-α结合域，该结合域属于MAT alpha1家族。 MAT2基因编码包含1个完整的HMG-box结合域，该结合域属于DNA结合蛋白中HMG-box家族的Ⅰ类成员，由3个螺旋结构组成，位于133～202个氨基酸残基之间，整体呈U型，结构比较松散，通过高度序列特异性与DNA的小沟结合，参与DNA的复制、转录、翻译等一系列的过程，从而参与玉米大斑病菌的有性生殖过程。 MAT1基因和MAT2基因侧翼序列的相似性高于93％。%In this study,we used the strains F 1-40(Mating type A) and 01-23(Mating type a) as materials.In order to obtain the full-length and the flanking sequence of MAT genes,the MAT1 gene of mating type A strain and the MAT2 gene of mating type a strain of Setosphaeria turcica were cloned by PCR and genome walking with the can-didate gene strategy .The conserved domain database of the full-length genes were analyzed .The flanking sequence of MAT1 and MAT2 genes were comprised by the Blast of genomic database of S.tucrica.The results suggested that both genes contain one introns .MAT1 encodes amino acids contain a complete MAT αd-omain,the domain as part of the MAT alpha1 family.MAT2 gene encodes amino acids ,including a complete MATA HMG-box combining with do-main,the domain as part of the DNA binding protein in the HMG -boxⅠclass members of the family ,such member containing a single HMG box ,composed of three helix ,which located between the 133-202 residues in the form of highly sequence specificity combined with DNA minor groove participating in the process of copy transcription and translation of DNA.Then participate in the process of sexual reproduction .Comparing the flanking sequence of MAT1 and MAT2 genes,we discovered the similarity was higher than 93%.