辣椒炭疽病生防菌的筛选鉴定及其防治作用研究

Screening and Identification of Biocontrol Strains of Colletotrichum capsici and Their Antagonistic Effect

为了分离利用防治辣椒炭疽病的高效生防菌株,从健康辣椒根部分离对辣椒炭疽病菌具有拮抗作用的生防菌,通过多相分类鉴定、盆栽试验、次生代谢产物检测、发酵液活性物质分离及稳定性检测,对生防菌进行分类鉴定和防治作用的初步探索。分离出2株抑菌效果好的链霉菌LX-4和LX-18,分别鉴定为Streptomyces angustmyceticus和S.luteogriseus。LX-4和LX-18对辣椒种子的萌发无影响,但对辣椒幼苗均有促生作用,对辣椒幼苗株高的增幅分别为21.61%和6.89%,对根长的增幅分别为6.76%和27.48%。LX-4和LX-18均可产生β-1,3-葡聚糖酶、蛋白酶、噬铁素和脂肪酶。两者的二氯甲烷、乙酸乙酯和正丁醇相粗提物均有抑菌活性,LX-18的乙酸乙酯相物质抑菌活性高;LX-4的正丁醇相物质抑菌活性高。LX-4和LX-18发酵液的的抑菌活性分别在pH 2~12和pH 6~12下稳定,均能在温度低于40℃时和光照96 h内稳定,但长时间在紫外照射下活性降低。结果表明,LX-4、LX-18对辣椒炭疽病有很好的生防应用前景。

The biocontrol strains which have good antagonistic effect on Colletotrichum capsici were isolated from healthy pepper roots.Through multiphase classification and identification,pot experiment,detection of secondary metabolites,separation and stability detection of active substances in fermentation broth,the identification and preliminary biocontrol mechanism of biocontrol strains were investigated.Two strains of Streptomyces,LX-4 and LX-18 were isolated and identified as Streptomyces angustmyceticus and S.luteogriseus,respectively.LX-4 and LX-18 had no effect on the germination of pepper seeds,but could promote the growth of pepper seedlings.LX-4 and LX-18 increased the plant height of pepper seedlings by 21.61%and 6.89%,and the root length by 6.76%and 27.48%,respectively.Both strains could produceβ-1,3-glucanase,protease,siderophore,and lipase.The crude extracts of dichloromethane,ethyl acetate and n-butanol from LX-4 and LX-18 showed antifungal activity.The ethyl acetate phase substance in LX-18 had high antifungal activity,n-butanol phase substance in LX-4 had high antifungal activity.The antifungal activities of LX-4 and LX-18 fermentation broth were stable at pH 2-12 and pH 6-12,respectively,both of them were stable at temperature below 40℃and light for 96 h,but the activity decreased under long time UV irradiation.Overall,it is suggested that the strain LX-4 and LX-18 have good application prospectsas biocontrol agents against Capsicum anthracnose.