猕猴桃细菌性溃疡病生防菌CXG2-5的筛选鉴定及微胶囊菌剂制备

Screening and identification of a biocontrol strain CXG2-5 against kiwifruit bacterial canker and preparation of microcapsules

摘要:

为了开发用于防治猕猴桃细菌性溃疡病的生防菌剂，通过平板对峙试验从猕猴桃根际土壤中分离筛选获得一株对猕猴桃细菌性溃疡病病原菌丁香假单胞菌猕猴桃致病变种(Pseudomonas syringae pv. actinidiae, Psa)有良好防治活性的菌株CXG2-5，并通过形态学观察、生理生化和分子生物学方法对其进行鉴定。使用离体枝条有伤接种法和叶盘真空渗透接种法对该菌株的室内防治效果进行测定，并通过荧光标记法和扫描电子显微镜对该菌株在叶脉上的扩展和定殖能力进行测定。随后，将该菌株制备成微胶囊菌剂，并评估其田间防治效果。结果表明，菌株CXG2-5被鉴定为食苯假单胞菌(Pseudomonas benzenivorans)，该菌株对Psa的抑菌圈直径达22 mm，抑制率为72.7%，具有良好的拮抗活性。同时，该菌株在离体枝条和叶片上对猕猴桃细菌性溃疡病的预防效果均优于治疗效果，预防效果分别达65.0%和92.4%。菌株CXG2-5微胶囊菌剂的田间防效达到60.89%，略低于20%春雷霉素，高于枯草芽孢杆菌可湿性粉剂。综上所述，菌株CXG2-5是防治猕猴桃细菌性溃疡病的潜力菌株，使用其制备的微胶囊菌剂具有良好的开发和应用价值。

Abstract:

To develop biocontrol agents for the control of kiwifruit bacterial canker, we isolated a strain CXG2-5 with inhibitory activity against Pseudomonas syringae pv. actinidiae (Psa), the pathogen of kiwifruit bacterial canker, from the rhizosphere soil of kiwifruit by the plate confrontation test. The strain was identified by morphological observation, physiological and biochemical tests, and molecular biological methods. The indoor control efficacy of the strain was determined by the inoculation of the strain into detached branches with wounds and into leaf discs by vacuum infiltration. The ability of the strain to expand and colonize leaf veins was determined by fluorescent labeling and scanning electron microscopy. Subsequently, the strain was prepared into microcapsules, the field control efficacy of which was evaluated. The strain CXG2-5 was identified as Pseudomonas benzenivorans. It demonstrated good antagonistic activity against Psa, with an inhibition zone diameter of 22 mm and an inhibition rate of 72.7%. The preventive effects of the strain on kiwifruit bacterial canker were better than the therapeutic effects on both detached branches and leaves, with the preventive effects reaching 65% and 92.4%, respectively. The control effect of microcapsules of this strain in the field reached 60.89%, which was slightly lower than that of 20% kasugamycin and higher than that of Bacillus subtilis wettable powder. In conclusion, strain CXG2-5 serves as a candidate for the control of kiwifruit bacterial canker, and the prepared microcapsules have good value for development and application.