棉花黑斑病病原鉴定及生防木霉菌株的筛选

摘要

从河南省部分地区感染黑斑病的棉花叶片上分离病原菌,并对其致病力、病原及其生防木霉菌株进行了研究.共分离到5株棉花黑斑病菌株.致病力分析表明,CHB-3的致病力比较强,病情指数达到89.3.对Y21c菌株的核糖体RNA基因内转录间隔区进行PCR扩增和序列测定,并在GenBank中进行Blast搜索和比对分析,根据rDNA-ITS序列分析结果并结合病菌的形态学特征,初步认为河南省棉花黑斑病的病原茵为细极链格孢菌(Alternaria tenuissima).利用平板对峙培养测定了7个木霉菌株对棉花黑斑病菌株CHB-3的拮抗作用,筛选到抑菌作用较好的木霉菌株TH,抑菌率为88.6%.%A lternaria leaf spot disease has spread around the world widely as a common infectious disease of cotton. Cotton leaves infected by Alternaria leaf spot were collected from some areas of Henan province. Five strains of the pathogenic fungi isolated from the sample were investigated for the morphological and biological characters. The rDNA-ITS genes of 2 isolates were amplified and sequenced. Based on the alignment analysis in GenBank database and morphological characters, the pathogen was identified as Alternaria tenuissima. Through confronting incubation, inhibition effect of seven Trichoderma harzianum strains against Alternaria leaf spot disease of cotton were tested. TH strains behaved best as the inhibition rate was 88.6％.