一株辣椒根腐病拮抗木霉菌Tb1的筛选与鉴定

Isolation and identification of an antagonistic fungus Tb1 against Fusarium solani(Mart.)causing pepper root rot

以辣椒根腐病菌(Fusorium oxysporum schlecht)为靶标菌,采用平板对峙法筛选出具有较高拮抗活性的菌株,研究该菌株的抑菌谱和稳定性,并结合菌株形态特征和18S rDNA基因序列分析确立其分类地位;采用生长速率法测定该菌株孢子悬液对辣椒根腐病菌和豇豆枯萎病菌抑制率,以期为辣椒根腐病的绿色防控提供理论依据。结果表明:筛选得到1株对辣椒根腐病菌拮抗作用较好的菌株Tb1,对辣椒根腐病抑制率为73.47%,经形态特征观察和18S rDNA基因序列分析,将其鉴定为短密木霉菌;同时Tb1菌株对番茄果腐病菌、豇豆枯萎病菌、茄子烂秆病菌、番茄枯萎病菌、茄子褐纹病菌、黄瓜枯萎病菌、番茄早疫病菌、西瓜枯萎病菌和番茄灰霉病菌等9种病原菌均具有不同的抑菌活性,抑制率在66.50%~85.79%;经10代继代培养后,Tb1菌株对辣椒根腐病的抑制率为80.87%;Tb1菌株孢子悬液(8.05×107cfu/mL)对辣椒根腐病原菌和豇豆枯萎病原菌抑制效果最好,其抑制率为98.35%和90.27%。

The strain with higher fungicidal activity against pepper root rot was obtained by confront culture method.The antifungal spectrum and stability of antagonistic strain were detected using the plate confrontation method.Its taxonomic status was defined using morphological identification,and 18S rDNA sequencing.Additionally,the inhibition rate of spore suspension was determined by the growth rate method against pepper root rot and cowpea wilt disease.The results showed that the antifungal activity of Tb1 against F.solani was 73.47%.Strain Tb1 was identified as T.brevicompactum based on morphological and cultural features,as well as multiple sequences analyses.The antifungal activity of Tb1 against R.solani,F.oxsyporum schl.f.sp.,P.vexans,F.oxysporum f.sp.lycopersici,P.vexans,F.oxysporum.sp.cucumebrium,A.solani,F.oxyporum f.sp.niveum and B.cinerea was from 66.50%to 85.80%.After the subculture of 10 generations,the antifungal activity of Tb1 against F.solani was 80.87%.Additionally,the control efficiency of Tb1 spore suspension(8.05×10^(7)cfu/mL)to pepper root rot and cowpea wilt disease was the best,and the fungicidal activity were 98.35%and 90.27%,respectively.