一株粪生毛壳菌的分离鉴定及其对辣椒枯萎病的防治效果

Isolation and Identification of Coprophilous Chaetomium Strain and Its Biocontrol Effect against Pepper Fusarium Wilt

本文采用平板对峙法和抑菌圈法从76株粪生真菌中筛选出1株辣椒枯萎病生防菌株LJ-S2L1,并利用菌落直径法、纸片扩散法、室内毒力测定和盆栽试验评价了其防病效果。结果表明,菌株LJ-S2L1对辣椒枯萎病菌抑菌率达71.67%,可使辣椒枯萎病菌菌丝发生隘缩或断裂,抑菌圈直径达32 mm;菌株LJ-S2L1发酵液和无菌发酵滤液均对辣椒枯萎病菌菌丝生长有抑制作用,抑制率分别达61.57%和56.48%。毒力测定结果表明,菌株LJ-S2L1发酵液对辣椒枯萎病菌的抑制率在1000μL/m L时达到72.10%,抑制中浓度为300.63μL/m L;盆栽试验防治效果达到71.8%。根据形态学特征结合其分子系统发育树分析,将菌株LJ-S2L1鉴定为球毛壳菌Chaetomium globosum。

The seventy-six coprophilous fungal strains were isolated from Pepper rhizosphere against Fusarium oxysporum by using dual-culture and inhibition zone assay. Among them, strain LJ-S2L1 with prominent potential was obtained on the basis of evaluation by colony diameter inhibition assay, Kirby-Bauer, toxicity measurement and pot experiments. The results showed that the inhibitory rate of LJ-S2L1 against F. oxysporum was 71.67%. The hyphae of pathogen was collapsed and fractured, and the diameter of inhibition zone was 32 mm by the inhibition zone assay. Both sterilized and non-sterilized fermentation liquid of LJ-S2L1 were effective against pathogen hyphae, and the inhibitory rates were 61.57% and 56.48%, respectively. In toxicity measurement, the inhibitory rate of LJ-S2L1 fermentation was 72.10% at the concentration of 1000 μL/m L, and the effective concentration（EC50） was 300.63 μL/m L. Pot trials showed that strain LJ-S2L1 effectively controlled pepper wilt with the inhibitory rate of 71.8%. Strain LJ-S2L1 was identified as Chaetomium globosum on the basis of the morphological characteristics and phylogenetic tree.