Screening of Mutation High-Yielding Biocontrol Bacterium BJ1 by Ion Beam Irradiation and Effect of Controlling Fusarium oxysporum cucunerinum Disease

BJ1 of Bacillus subtilis is an important biocontrol factor in control of fungus disease. In order to improve the antagonistic ability of the strain, and obtain high-efficiency strains,¹²C⁶⁺ of different doses and linear energy transfer (LET) was used to irradiate the biocontrol bacterium BJ1. The optimum dose and LET of ion beam irradiation for the BJ1 are 200-400 Gy and 60 keV/μm, respectively. The antagonistic ability is increased by 2%-21%. The control effect of mutation to Fusarium oxysporum f. sp. cucunerinum is increased by 17.48% over that of BJ1, and mutation also has better plant growth promoting effect.