中国北方玉蜀黍黑粉菌交配型a位点鉴别及遗传多样性分析

利用特异性引物对2017年采自7个省(自治区)的84份玉米瘤黑粉病菌进行交配型a位点鉴别，采用相关序列扩增多态性(ISSR)分子标记技术对供试菌株进行遗传多样性分析，分析我国北方玉米主要产区玉蜀黍黑粉菌交配型a位点基因型种类及其遗传多样性水平。结果表明，玉蜀黍黑粉菌交配型a位点基因型主要有mfa1、mfa2和mfa1+mfa2三个种类，84株菌株中，mfa1基因型和mfa1+mfa2基因型均有31株，占鉴定株数的36.9%；22株为mfa2位点，占鉴定株数的26.2%。通过筛选出的8条ISSR引物共扩增出61条清晰条带，特异性条带55条，多态性位点所占比例为90.2%。UPGMA聚类分析结果表明，供试菌株遗传相似系数介于0.59～0.92，在遗传相似系数为0.65时供试菌株被分为6个类群，表现出丰富的遗传多样性。ISSR揭示的玉蜀黍黑粉菌遗传多样性、交配型a位点基因型以及地理来源之间的关系分析结果表明，菌株的遗传类群和交配型a位点基因型之间无密切关系，并且两者与菌株地理来源也无明显相关性。

Mating Type a Locus Identification and Genetic Diversity Analysis of Ustilago maydis in North China

To clarify the mating type a locus and the genetic diversity of Ustilago maydis in the main corn producing areas in North China.The mating type a locus identification and genetic diversity analysis of 84 corn smut isolates collected from 7 provinces (autonomous regions) were carried out by the inter simple sequence repeat (ISSR) molecular marker technology.The results showed that there were three genotypes of mating type a locus of Ustilago maydis,mfa1,mfa2 and mfa1+mfa2.In the 84 isolates,mfa1 genotype and mfa1+mfa2 genotype both had 31 isolates,accounting for 36.9% of the total;22 isolates were mfa2,accounting for 26.2%.The results demonstrated that 55 specific bands were amplified by 8 primers in the 61 bands,the proportion of loci was 90.2%.UPGMA cluster analysis showed that the genetic similarity coefficient of the tested isolates ranged from 0.59 to 0.92,and when the threshold was 0.65,all isolates were divided into 6 groups,showing rich genetic diversity.The analysis results of the relationship among the genetic diversity,genotypes of mating type a locus and geographical origins of Ustilago maydis revealed by ISSR indicated that there was not a close relationship between the genetic groups and genotypes of mating type a locus of the tested isolates,and there was no obvious correlation between them and the geographical origins.