Screening and controlling mechanism of antagonistic yeast against peach brown rot

Abstract:

[Background] Brown rot is one of the most destructive diseases in peaches worldwide, causing serious economic loss of the peach industry. [Objective] To identify the causative agent of peach brown rot in Taigu District of Shanxi Province and screen efficient antagonistic yeast against the pathogen causing peach brown rot. [Methods] The fungus causing brown rot was isolated from the symptomatic fruits of the peach variety ‘Cuiyu’ and identified by morphological observation, pathogenicity test, and molecular methods. The antagonistic yeast strains were screened by in vitro and in vivo assays and identified based on morphological, physiological, biochemical characteristics and molecular evidence. Moreover, the activities of defense-related enzymes and other indicators were determined to evaluate the effects of the antagonistic yeast treatment on peach resistance to brown rot. [Results] Monilinia fructicola was identified as the main fungus causing the brown rot of peach fruits in Taigu District of Shanxi Province. The optimal antagonistic yeast strain HYA-4.1 was identified as Wickerhamomyces anomalus, which showed an inhibition rate of 78.31% on the mycelia of M. fructicola and increased the activities of antioxidant-related enzymes in peach fruits. The results suggested that the strain inhibited peach brown rot. [Conclusion] We identified the causative agent of peach brown rot and screened out an antagonistic yeast strain with significant inhibitory effect, which provided a reference for the screening and application of biocontrol strains.