Bacillus subtilis NJ-18菌株对番茄早疫病菌的颉颃作用研究

Biological Control of Alternaria solani by Bacillus subtilis NJ-18

采用杯碟法测定表明,枯草芽孢杆菌Bacillus subtilisNJ-18菌株对番茄早疫病菌Alternaria solani的菌丝生长有强烈颉颃作用,抑菌带宽度为21.5mm。NJ-18的培养滤液能使A.solani菌丝肿胀畸形。利用利福平抗性标记证明NJ-18能够在番茄根、茎、叶内定殖,土壤浇灌30d后,NJ-18在番茄根茎内定殖的菌量仍然达到103CFU/g植株鲜重。NJ-18发酵液喷施处理盆栽番茄苗后接种,14d后对番茄早疫病的防治效果为72.9%,显著高于50%异菌脲2000倍液的防效45.7%。

Strong inhibition of Bacillus subtilis strain N J-18 on mycelia growth of Alternaria solani was observed in the antagonistic tests by cylinder plate methods, and the inhibition width was 21.5 mm. Observation under microscope found that the supernatant of fermentation from NJ-18 could make the pathogen hyphae cells malformed and swelled, and consequently the growth of the pathogen was inhibited. Determining of the colonization in potato plants by the signed rifampicin-resistance in NJ-18 showed that it could colo- nize well in the plants, the colonization quantity of NJ-18 in the root and stem of the potato detected 30 days after fermentation irrigation was 10^3 CFU/g plant＇s fresh weight. In pot experiment, we inoculated the tomato plants with the spore suspensions of Alternaria solani after spraying the fermentation of N J-18, the results were investigated in 14 days and the efficacy in controlling the disease was 72.9%, which was signifi- cantly higher than 45.7%, the efficacy resulted from spray treatment of 2000 fold dilution of 50% iprodione wetable powder.