生物技术通报2024，Vol.40Issue(11)：202-213,12.DOI:10.13560/j.cnki.biotech.bull.1985.2024-0202
梨火疫病拮抗菌JK2的筛选鉴定及发酵条件优化
Screening and Identification of Antagonistic Bacterium JK2 Against Fire Blight Disease and the Optimization of Its Fermentation Conditions
摘要
Abstract
[Objective]Fire blight is a devasting bacterial disease caused by Erwinia amylovora,which seriously affects the production safety of rosaceous plants,such as pears and apples.To explore potential bacterial strains as biocontrol agents for managing fire blight,antagonistic bacteria were isolated from fruits and rhizosphere soil of Malus spectabilis.[Method]Biocontrol strains were isolated using plate dilution method,using E.amylovora as the indicator bacterium.Strains with antagonistic effects were screened and rescreened using plate confrontation method and Oxford cup diffusion method.The antagonistic bacteria were identified by morphological observation,physiological and biochemical tests and 16S rDNA sequence homology analysis.The fermentation of antagonistic bacteria were optimized using the single-factor procedure and orthogonal experiments.The fermentation broth of antagonistic bacteria was used to determine the in vitro antagonistic activity against E.amylovora on the fruit of wild apple(Malus sieversii).[Result]Four strains with strong antagonistic effects were isolated(JK1,JK2,JK3 and JK4),and the strain JK2 showed the strongest antagonistic effect on E.amylovora with a bacteriostatic potency of 359.7 mm/mL.Based on morphological,physiological and biochemical characteristics and 16S rDNA sequence analysis,the strain JK2 was identified as Bacillus velezensis.The optimized culture conditions were determined as follows:initial pH of 6.66,culture temperature of 30.6℃,inoculation size of 3.9%,and rotation speed of 208 r/min.Under these conditions,the number of viable counts was 1.29×109 CFU/mL,a significant increase(53.1%)as compared to the control.The control effects in the fruit of wild apple in greenhouse showed that the disease index of the protective test inoculated with strain JK2 significantly reduced,reaching 65.88%,and the protective effect was better than the therapeutic effect.[Conclusion]Strain JK2 demonstrates considerable potential for controlling fire blight,which is a promising candidate for use as a biological control agent.关键词
梨火疫病/生物防治/贝莱斯芽孢杆菌/发酵条件Key words
fire blight disease/biological control/Bacillus velezensis/fermentation conditions引用本文复制引用
马云涛,胡丽娜,孙文婧,唐莲庚,孙思远,邓欣雨,孙黎..梨火疫病拮抗菌JK2的筛选鉴定及发酵条件优化[J].生物技术通报,2024,40(11):202-213,12.基金项目
国家级大学生创新创业训练计划(202310759069),兵团科技计划(2023AB004-03) （202310759069）
