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Chinese Journal of Biological Control ›› 2023, Vol. 39 ›› Issue (5): 1253-1265.DOI: 10.16409/j.cnki.2095-039x.2023.02.053

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The Study on Screening, Identification and Its Potential Application of Biocontrol Agents against Fusarium oxysporum f. sp. niveum

XU Peiling, HAN Wenxin, WANG Gang, CHEN Wen, GAO Hongshan, Lü Minghui, YANG Xiangming, ZHU Yanze, JIANG Chunhao   

  1. College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2023-03-28 Online:2023-10-08 Published:2023-10-25

Abstract: To obtain biocontrol strains with high control efficacy against watermelon Fusarium wilt, 32 strains with high chitinase activity were screened in this study, by using colloidal chitin as the only carbon source, from more than 1000 strains isolated from mangrove rhizosphere soil in Zhuhai, Guangdong province. Furthermore, 10 strains with high efficacy were obtained by using plate antagonism assay. The greenhouse results showed that the 10 strains had various growth promotion and disease prevention effects, among which the strain PL-29 treatment showed the best control efficacy of watermelon Fusarium wilt compared with the control. The control efficacy of strain PL-29 was 63.11%, and its growth promotion effect was also significant. The strain PL-29 was identified as Streptomyces flavotricini by morphological, physiological and biochemical characteristics and 16S rDNA phylogenetic analysis. In addition, the result of antagonism spectrum assay showed that the strain had antagonistic ability against Phytophthora capsici, Botrytis cinerea, Rhizoctonia solani and other pathogens. Further study on the inhibitory effect of strain PL-29 on Fusarium oxysporum showed that strain PL-29 could inhibit the formation and germination of F. oxysporum spores, and thus inhibit the growth of the pathogen. In addition, it can impair the integrity of the plasma membrane of F. oxysporum and induce ROS accumulation. These results indicate that S. flavotricini PL-29 has high potential application value in the control of watermelon Fusarium wilt.

Key words: chitin, biological control, Fusarium wilt of watermelon, Streptomyces flavotricini

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