棉花枯萎病生防菌的筛选及其抑菌机理初探

Screening of Biocontrol Bacteria against Cotton Fusarium Wilt and Preliminary Study on Its Bacteriostatic Mechanism

为获得能够防治棉花枯萎病的生防菌株,本试验从发生棉花枯萎病的棉田中筛选抑菌效果较好的生防菌株;通过形态学特征、生理生化特征与分子生物学方法对其进行菌种鉴定,并通过平板对峙法检测生防菌株粗提物对尖孢镰刀菌的防治效果及稳定性。结果筛选到一株抑菌效果较好的菌株JNJX-2,经鉴定为多粘类芽孢杆菌。该菌株的抑菌谱较广泛,对灰葡萄孢、离蠕孢菌、禾谷镰刀菌等均具有一定的抑制作用。该菌株可以产生几丁质酶、蛋白酶、果胶酶、纤维素酶。通过萃取与旋转蒸发相结合的方式,得到了该菌株的抑菌粗提物,其性质较为稳定,对温度、紫外线、蛋白酶不敏感,对碱性环境敏感。

The aim of this study was to obtain biocontrol strains against cotton Fusarium wilt.The biocontrol strains with better bacteriostasis effect were screened from the cotton fileds with Fusarium wilt occurrence.The strains were identified by morphological,physiological and biochemical characteristics and molecular biology methods,and the control effects and stability of crude extract of biocontrol strains to Fusarium oxysporum were tested by plate confrontation.The results showed that a strain named JNJX-2 with better bacteriostasis effect was screened out and identified as Bacillus polymyxa.The bacteriostasis spectrum of this strain was extensive,and it had certain bacteriostasis effects on Botrytis cinerea,Bipolaris and Fusarium graminearum.This strain could produce chitinase,protease,pectinase and cellulase.The crude antimicrobial extract of this strain was obtained by the combined method of extraction and rotary evaporation.Its properties were stable,and it was insensitive to temperature,ultraviolet radiation and protease,but sensitive to alkaline environment.