棉花黄萎病拮抗菌KF-43-1的鉴定与3种处理田间防治效果对比

Identification of strain KF-43-1 against cotton verticillium wilt and comparison of biocontrol effects among three application methods in the field

摘要:

【背景】棉花黄萎病具有棉花“癌症”之称，对棉花的产量和纤维质量造成较重危害，生物防治以绿色安全等优点成为防治棉花黄萎病应用领域的重点研究内容，因此开发新的生物菌剂防治棉花黄萎病对棉花生产工作具有重要意义。【目的】通过对具有拮抗棉花黄萎病菌作用的放线菌KF-43-1进行初步鉴定及生理生化测定，明确最佳使用方式，为开发新的防治棉花黄萎病生物菌剂提供支持。【方法】对菌株KF-43-1进行分子鉴定，观察其形态特征及生长特性，测定菌株KF-43-1对病原真菌的抑菌效果，明确菌株KF-43-1的生理生化特性，验证放线菌KF-43-1不同使用方式对棉花黄萎病的田间防治效果。【结果】培养特征和显微特征及分子鉴定结果将菌株KF-43-1鉴定为白浅灰链霉菌(Streptomyces albogriseolus)；菌株KF-43-1对病原菌V991抑制效果达到82.05%，防效高于放线菌5406，对尖孢镰刀菌萎蔫专化型ST89抑制效果达到25.81%，低于放线菌5406的防效；菌株KF-43-1无荧光反应，能够使明胶液化、淀粉水解、甲基红试验阳性、可以产生黑色素，不具备分解纤维素的能力，菌株KF-43-1在pH 7.0-8.0时生长情况良好，在盐浓度为2%的高氏一号培养基上生长受到抑制并表现出一定的耐盐性，使用拮抗菌KF-43-1菌液制作种衣剂对棉花黄萎病的防效高于离心液包衣和离心液叶面喷施，说明拮抗菌KF-43-1在土壤中定殖后对棉花黄萎病暴发具有更好的抑制效果。【结论】棉花黄萎病拮抗放线菌KF-43-1作为一种新型生防菌，可为开发防治棉花黄萎病的生物菌剂提供生防菌资源，具有良好的开发价值和应用价值。

Abstract:

[Background] Cotton verticillium wilt, known as the “cancer” of cotton, causes serious harm to the yield and fiber quality of cotton. Biocontrol with eco-friendliness and high safety has become the key research content in the prevention and treatment of cotton verticillium wilt. Therefore, developing new biological agents to control cotton verticillium wilt is of great significance for cotton production. [Objective] To preliminarily identify and characterize the actinomycete strain KF-43-1 with antagonistic effect on cotton verticillium wilt and determine the best application method of this strain, so as to provide support for the development of new biocontrol agents against cotton verticillium wilt. [Methods] Strain KF-43-1 was identified based on molecular evidence, and its morphological and growth characteristics were observed. The inhibitory effects of KF-43-1 on pathogenic fungi were determined. The physiological and biochemical characteristics of the strain were determined, and verify the field control effect of different uses of actinomyces KF-43-1 on cotton verticillium wilt. [Results] Strain KF-43-1 was identified as Streptomyces albogriseolus. It showed inhibitory effect of 82.05% on the pathogen V991, which was higher than that of the actinomycete strain 5406. It demonstrated the inhibitory effect of 25.81% on Fusarium oxysporum ST89, which was lower than that of strain 5406. Strain KF-43-1 had no fluorescence reaction and can liquefy gelatin, hydrolyze starch, yield positive results in the methyl red test, and produce melanin. However, it did not have the ability to decompose cellulose. Strain KF-43-1 grew well at pH 7.0–8.0, and was inhibited in Actinomycetes culture medium with 2% salt concentration and showed some salt tolerance. The effect of antagonistic KF-43-1 on cotton verticillium wilt was higher than that of centrifuge coating and centrifuge spraying, indicating that antagonistic KF-43-1 had better inhibition effect on cotton verticillium wilt outbreak after colonizing in soil. [Conclusion] The actinomycete strain KF-43-1 serves as a candidate for the development and application of biological agents for the prevention and control of cotton verticillium wilt.