The Study of Metschnikowia pulcherrima E1 in the Induction of Improved Gray Spot Disease Resistance in Loquat Fruit

In this study, the dominant pathogenic fungus of gray spot disease in loquat, which was isolated from postharvest decaying loquat fruits in Zhenjiang, was identified as <i>Pestalotiopsis vismiae</i> (<i>P. vismiae</i>) by morphological characteristics and DNA sequencing. At the same time, a strain of yeast E1, which could effectively inhibit the pathogen, was isolated from the loquat leaves and soil and identified as <i>Metschnikowia pulcherrima</i> (<i>M. pulcherrima</i>) by morphological and molecular biological characteristics. It significantly reduced the natural decay of loquat fruits without affecting fruit quality. <i>Metschnikowia pulcherrima</i> E1 (<i>M. pulcherrima</i> E1) exhibited significant biocontrol efficacy against <i>P. vismiae</i>, the causal agent of gray spot in loquat, reducing disease incidence to 22.73% compared to 100% in the control group. Transcriptome analysis revealed 1444 differentially expressed genes (DEGs) (1111 upregulated, 333 downregulated), with key genes (<i>CML19</i>, <i>XTH23</i>, <i>GSTU10</i>) validated by RT-qPCR. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis highlighted enrichment in plant-pathogen interactions, glutathione metabolism, and phenylpropanoid biosynthesis. These findings provided molecular insights into yeast-induced resistance, bridging biocontrol applications with mechanistic studies.