Biocontrol activities of grey mould of grapes with the volatile organic compounds generated by yeast HXMG-1 isolated from grapes

The pathogens are reduced by volatile organic compounds (VOCs) generated by yeasts play an important role in controlling postharvest diseases. The yeast HXMG-1, which works effectively against the grey mould pathogen of grapes (Botrytis cinerea), was evaluated for its potential to generate volatile organic compounds as one of its modes of action. A double Petri dish assay was used to evaluate the effect of VOCs produced by HXGM-1 on mycelial and spore development of the target pathogens. Compared to the control, the VOCs produced by yeast HXMG-1 significantly reduced the growth of mycelium and spore germination of Botrytis cinerea. Specifically, the mycelial growth of Botrytis cinerea was completely restricted and the rate of spore germination of Botrytis cinerea was only 20.11% at a concentration of 1 × 10⁹ CFU/mL. It was also found that the VOCs could significantly inhibit mycelial growth with an inhibition of 82.46% at a concentration of 1 × 10⁸ CFU/mL. The VOCs caused the mycelium to grow curved, resulting in larger mycelial tips, fewer nuclei, and shorter mycelial septum spacing. In vivo tests, noninjure or injure grapes were artificially inoculated with the pathogen hyphal disc followed by biofumigation with VOCs produced by yeast HXMG-1, and the treatments (Wp2 and Wp3) significantly controlled pathogenic infection, confirming the results of in vitro tests. By molecular biological identification based on comparative sequence analysis of the 18S rDNA gene, the HXMG-1 strain was identified as Hanseniaspora uvarum. Through the creation of a phylogenetic tree, HXMG-1 was recognised as a member of the Ascomycota, Hemiascomycota, Yeasts, and Hanseniaspora sp. families. In conclusion, the yeast strain HXMG-1 created VOCs that significantly inhibited the development of Botrytis cinerea on grapes and is expected to be further developed and utilised. This study lays the foundation for the use of Hanseniaspora sp. for biological control of postharvest disease.