辣椒疫病生防菌的筛选、鉴定及其抑菌机理初探

Isolation,Identification and Biocontrol Mechanism of Antagonistic Bacteria against Phytophthora capsici

采用平板稀释法和平板对峙试验,从武汉、荆州、宜昌和荆门等地的辣椒根际土壤中分离到185株细菌,筛选到1株具有高效拮抗辣椒疫霉菌(Phytophthora capsici)的生防菌Bs04。通过形态学观察、生理生化指标测定、16S r DNA序列测定及进化树构建,确定菌株Bs04为枯草芽孢杆菌(Bacillus subtilis)。Bs04对辣椒疫霉菌丝生长抑制率达80%,同时对烟草黑胫病菌(Phytophthora parasitica var.nicotiana)、棉花黄萎病菌(Verticillium dahliae)、棉花枯萎病菌(Fusarium oxysporum f.sb.vesinfectum)和黄瓜立枯病菌(Rhizoctonia solani)具有明显的抑制作用。利用光学显微镜观察Bs04对辣椒疫霉菌丝形态的影响,发现菌丝分支增多、顶端畸形、原生质浓缩及生长缓慢等现象,表明Bs04具有显著的抑菌作用。

One hundred and eighty-five bacteria strains were isolated from soil samples taken from the rhizosphere of pepper from Wuhan, Jingzhou, Yichang and Jingmen of Hubei province with plate-dilution method. One strain named as Bs04 was screened with fungi growth inhibition method, having the strongest antagonistic activity against Phytophthora capsici. The Bs04 was identified as Bacillus subtilis based on its morphological and biochemical characteristics, 16S rDNA sequences and alignment. The strain Bs04 can inhibit the myeelium growth of P. capsiei with the inhibitory effect of 80%. The strain Bs04 had antifungal activities toward other plant pathogens including P. parasitica var. nicotiana, Verticillium dahliae, Fusarium oxysporum f.sp. vesinfectum and Rhizoctonia solani. The phenomenon of increasing mycelium branches, hyphal top malformation, protoplasm concentration and slowing growth indicated that the strain Bs04 could control P. capsici strongly.