Biocontrol Effect of Bacillus siamensis Y-54 against Tomato Leaf Mold

ZENG Wanning; WANG Yanxuan; WANG Fanzhen; CHEN Zhaorong; LIU Huiqin; JIANG Yongcheng; Azmat·Turhorn; LI Baotong

doi:10.15933/j.cnki.1004-3268.2024.03.010

Abstract：In order to clarify the biocontrol effect of Bacillus siamensis Y-54 against tomato leaf mold and provide a scientific basis for the biological control of tomato leaf mold,the inhibitory effect of strain Y-54 on Cladosporium fulvum was measured by confrontation and microscopic observation,and the colonization of antagonistic strain Y-54 in tomato was studied by irrigation method.The growth promoting effect of the strain Y-54 on seed germination and seedling growth of tomato was studied by soaking seed method and filling root method.The control effect was measured by pot experiment.The result showed that strain Y-54 and its fermentation broth and sterile filtrate all had strong inhibitory effects on C.fulvum,with inhibition rates reaching 78.42%,86.42%and 91.26%,respectively.The sterile filtrate could make mycelium of C.fulvum deform,bend,shrink,expand and break.The strain Y-54 could colonize in the roots,stems and leaves of tomato within 30 days.The colonization of the strain Y-54 reached the peak at 15-18 d.The colonization in the root was always higher than that in other parts.Strain Y-54 could effectively promote seed germination.The germination rate of fermentation broth(0×)treatment was the highest,reaching 93.33%.Moreover,it could effectively promote the increase of root length,plant height,fresh weight,chlorophyll and other indexes of seedlings.The growth promoting effect of 0×,10×and 20×fermentation broth was significantly higher than that of the control with sterile water.The control effects of strain Y-54 fermentation broth on tomato leaf mold within 7 days and 14 days were 68.04%and 71.07%,respectively,close to that of phenoxymethyclozole treatment,and significantly higher than that of carbendazim treatment.In summary,the strain Y-54 had good control effect on tomato leaf mold,and it was a biocontrol bacterium worth further development and utilization.