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Chinese Journal of Biological Control ›› 2026, Vol. 42 ›› Issue (4): 945-957.DOI: 10.16409/j.cnki.2095-039x.2026.02.042

• RESEARCH REPORTS • Previous Articles    

Control Efficacy of Serratia plymuthica KRS006 on Cotton Verticillium Wilt

LIU Xinxin1, TANG Mengyu1,2, ZHANG Dandan1, CHEN Jieyin1, JIANG Ming2, WANG Dan3   

  1. 1. State Key Laboratory for Biology of Plant Diseases and Insect Pests/Institute of Plant Protection/Chinese Academy of Agricultural Sciences, Beijing 100193, China;
    2. College of Life Science and Technology, Mudanjiang Normal University, Mudanjiang 1570003, China;
    3. College of Forestry, Zhejiang A & F University, Hangzhou 311300, China
  • Received:2025-03-28 Published:2026-08-26

Abstract: Cotton Verticillium wilt is a soil-borne vascular disease caused by the fungus Verticillium dahliae. In this study, a bacterial strain designated KRS006, exhibiting significant antagonistic activity against this pathogen, was isolated from the rhizosphere soil of healthy cotton plants. To determine its taxonomic status and assess its potential for biological control, the strain was identified as Serratia plymuthica through polyphasic characterization, including morphological traits, physiological and biochemical assays, as well as 16S rRNA and gyrB gene sequence analyses. The strain demonstrated broad-spectrum antifungal activity against seven plant pathogenic fungi. Moreover, it possessed multiple plant-growth-promoting traits, such as phosphate and potassium solubilization, nitrogen fixation, siderophore production, and the ability to secrete protease, lipase, and chitinase. In greenhouse experiments, KRS006 achieved a control efficacy of 92.3% against cotton Verticillium wilt and significantly promoted cotton plant growth. To gain insights into the antagonistic mechanism, scanning and transmission electron microscopy were employed to observe the ultrastructural interactions between KRS006 and V. dahliae. The microscopic analyses clearly revealed that strain KRS006 caused severe disruption and disintegration of the hyphal cell membrane structure of the pathogen, suggesting a direct detrimental effect on cellular integrity. Furthermore, the volatile organic compounds(VOCs) produced by strain KRS006 were identified by gas chromatography–mass spectrometry(GC-MS) as dimethyl disulfide, 1-chloropentane, and dimethyl trisulfide. In vitro bioassays confirmed that all three purified volatile compounds exerted a pronounced inhibitory effect on mycelial growth of V. dahliae, with dimethyl trisulfide showing the strongest activity, indicating that these volatiles contribute substantially to the antifungal action. Collectively, our findings demonstrate that S. plymuthica KRS006 possesses potent biocontrol efficacy against cotton Verticillium wilt through multiple mechanisms, including direct mycoparasitism via lytic enzymes, membrane disruption, and volatile-mediated inhibition, in addition to its plant-growth-promoting properties. Therefore, strain KRS006 represents a promising microbial resource for the sustainable and environmentally friendly management of cotton Verticillium wilt in agricultural systems.

Key words: cotton Verticillium wilt, Verticillium dahliae, Serratia plymuthica, biological control, growth promoting effect

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