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Chinese Journal of Biological Control ›› 2021, Vol. 37 ›› Issue (4): 837-845.DOI: 10.16409/j.cnki.2095-039x.2021.04.001

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Identification of Antagonistic Bacteria CL01 against Pear Anthracnose and Its Anti-Pathogenic Activity

LI Chaohui, BAO Yan, MIAO Chengqi, LING Jun, SUN Weibo, ZHAO Yancun, XU Huiyong, LIU Fengquan   

  1. Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences/Jiangsu Province Key Laboratory of Food Quality Safety-Ministry of State Construction of National Key Laboratory Breeding Base, Nanjing 210014, China
  • Received:2020-12-24 Published:2021-09-18

Abstract: In order to obtain antagonistic bacteria for the biocontrol of pear anthracnose, we isolated bacteria from the rhizosphere soil of pear orchards in Jurong, Jiangsu Province. One of the isolates named CL01 showed good antagonistic effect on C. fructicola. The isolate CL01 was identified as Paenibacillus ottowii by morphology, physiological and biochemical characterization, and 16S rDNA and rpoB gene sequence analysis. CL01 can inhibit the growth of C. fructicola mycelium, and the inhibition zone width reaches (8.2±0.4) mm on PDA plates. The marginal hyphae of the inhibited fungal colony become dense, hyperbranched and locally swollen. Scanning electron microscope observation revealed that the CL01 fermentation broth can destroy the integrity of the cell wall of C. fructicola, causing the hyphae to shrink and collapse. CL01 fermentation broth can also reduce the germination rate of C. fructicola conidia and inhibit the elongation of the germ tube, and conidia germination rate decreased to less than 50% after treatment with fermentation broth. The n-butanol crude extract of CL01 fermentation broth had antagonistic activity against C. fructicola, and the inhibition zone width can reach (7.3±0.2) mm. Both the CL01 fermentation broth and the n-butanol crude extract of the fermentation broth can effectively inhibit the expansion of pear anthracnose spots, and the control efficacies reached 62.0% and 83.0%, respectively. In addition, CL01 also showed antagonistic activity against a variety of phytopathogens and had the potential to be developed as a biocontrol agent.

Key words: pear anthracnose, antagonistic bacteria, Paenibacillus, biocontrol

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