VmMon1-Ccz1 Complex Is Required for Conidiation, Autophagy, and Virulence in .

Apple Valsa canker caused by is a serious disease in eastern Asia, especially in China. In our previous proteomics study, monensin sensitivity 1 protein in () was identified to be significantly upregulated during infection. It was reported Mon1 protein formed a heterodimer called MC (Mon1-Ccz1) complex with caffeine, calcium, and zinc sensitivity 1 protein (Ccz1) in yeast. However, Ccz1 had not been identified in plant-pathogenic fungi such as and . Here, we identified a Ccz1 ortholog in , by using DELTA-BLAST. The interaction of and were verified using yeast two-hybrid assay, bimolecular fluorescence complementation, and co-immunoprecipitation assays. Further yeast three-hybrid screenings determined that (Ras-related protein in ) interacted with the MC complex. Targeted gene deletion showed that the ∆ and ∆ mutants were defective in vegetative growth, conidiation, and pathogenicity. In addition, both mutants were more sensitive to osmotic and oxidative stresses and intracellular protein transport inhibitors. Cytological examination revealed that the ∆ and ∆ mutants were impaired in vacuole fusion and autophagy. More importantly, expression of pectinase genes decreased in both mutants compared with those of the wild type during infection. Overall, our study identified and genes in and provided evidence that and are critical components that modulate vacuole fusion and autophagy, thereby affecting the development, conidiation, and pathogenicity of . [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.