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Acta Prataculturae Sinica ›› 2021, Vol. 30 ›› Issue (9): 137-149.DOI: 10.11686/cyxb2020333

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A preliminary study of the antifungal activity and antagonism mechanisms of Trichoderma spp. against turfgrass pathogens

Wu ZHANG(), Jin-yu YANG, Xiang LU, Jin-mei LIN, Xue-li NIU()   

  1. Lingnan Normal University,Zhanjiang 524048,China
  • Received:2020-07-14 Revised:2020-10-10 Online:2021-08-30 Published:2021-08-30
  • Contact: Xue-li NIU

Abstract:

Trichoderma spp., is an antagonistic group of microorganisms widely found in nature and many species have important biocontrol value for use against plant pathogens. In order to evaluate Trichoderma spp. as a potential biocontrol agent for turfgrass disease, the antagonistic effects of four Trichoderma strains against 14 turfgrass pathogens were determined by agar confrontation culture and the mechanism of inhibition was studied by microscopic observation, the ‘cellophane method’ and bacteriostatic testing of crude extract. The results showed that tested Trichoderma spp. isolates had antagonism against all tested pathogens. Among the tested Trichoderma spp. isolates, an isolate designated SQ-1Q-18 had the greatest antibacterial efficacy. The antagonistic activity against Rhizoctonia zeae and Laetisaria fuciformis was scored as level I, with 100% inhibition rate; for Botrytis cinereaColletotrichum hainanese and Rhizoctonia solani the antagonistic activity was scored as level Ⅱ, with over 80% inhibition rate for the most potent Trichoderma isolate, and an average inhibition rate against these three pathogens of up to 72.8%. Further study of the inhibitory mechanism of the SQ-1Q-18 isolate on 14 pathogens was that Trichoderma surrounded the growth space of pathogens by generating a bacteriostatic circle, and covered and inserted into the pathogen colony and entwined with it to make the pathogen mycelium become thin, constricted and even broken. Trichoderma could also penetrate directly into a pathogen mycelium to absorb nutrients and cause mycelium cytolysis. In addition, the SQ-1Q-18 isolate could produce antagonistic compounds with inhibitory activity against the turfgrass pathogens. The antagonistic substances produced by the cellophane culture method had strong antagonistic effects against Sclerotinia homoeocarpaNigrospora sphaerica and L. fuciformis, and the relative inhibitory rate was as high as 91.77%, 89.80% and 79.59%, respectively. The inhibition rate of Trichoderma crude extract against S. homoeocarpa and Bipolaris peregianensis was 43.60% and 42.91%, respectively. Furthermore, the SQ-1Q-18 isolate was identified as Trichoderma harzianum by morphological characteristics and ITS-rDNA sequence. This study provides scientific data for the research and development of a biocontrol agent for efficient control of turfgrass fungal diseases.

Key words: Trichoderma spp., turfgrass pathogens, antibacterial activity, antagonistic mechanism, Trichoderma harzianum