为明确拮抗真菌HTC对辣椒疫霉Phytophthoracapsici的拮抗机制,采用平板对峙、形态学鉴定和18SrDNA序列比对分析等方法对菌株HTC进行了鉴定,并研究其发酵液与抗生物质粗提液对辣椒疫霉不同发育阶段的影响。经鉴定,菌株HTC为金色毛壳菌Chaetomiumaureum。在平皿对峙试验中,菌株HTC的红色分泌物能抑制辣椒疫霉菌丝的生长,抑制率为59.1%,后期HTC茵丝可缠绕并降解辣椒疫霉菌丝。发酵液与抗生物质粗提液对辣椒疫霉不同发育阶段均有抑制作用,发酵液对辣椒疫霉菌丝生长的抑制率高达97.58%,对辣椒疫病的防治效果均高于70%。浇灌发酵液后,可提高辣椒苗的苯丙氨酸解氨酶、过氧化物酶、多酚氧化酶的活性,并明显促进辣椒苗生长,鲜重和干重增加32.27%和18.09%。研究表明,金色毛壳菌菌株HTC是一株具有开发潜力的生防菌株。
To investigate the antagonistic mechanism of the fungus strain HTC against Phytophthora capsi- ci, the plate confrontation, morphologic identification and sequence analysis of 18S rDNA were used to identify the strain HTC, and the effects of fermentation broth and antibiotic crude extracts on different de- velopment stages of P. capsici were conducted. The strain HTC was identified as Chaetomium aureum. In- hibition of mycelial growth of P. capsici was 59.1% by the strain HTC in plate confrontation. Red secre- tion from strain HTC could inhibit mycelial growth of P. capsici. Hyphae of P. capsici were coiled and di- gested by hyphae of strain HTC at late stage. Different development stages of P. capsici were inhibited by both fermentation broth and antibiotics crude extracts. Fermentation broth showed 97.58% inhibition rate in mycelial growth of P. capsici. Control efficiency was more than 70% by both fermentation broth and an- tibiotics crude extracts. After treatment with fermentation broth, the activities of defense enzymes inclu- ding phenylalanine ammonia lyase, peroxidase, polyphenol oxidase in pepper plants increased and their resistance to disease enhanced. Fermentation broth from the strain HTC was able to significantly promote growth of pepper seedlings. Fresh weight and dry weight increased by 32.27% and 18.09%, respective- ly, after treatment with fermentation broth. Therefore, C. aureum strain HTC is a strain with potential for biological control of P. capsici.