Cpvma1, a Vacuolar H-ATPase Catalytic Subunit of , is Essential for Virulence and Hypovirus RNA Accumulation.

The vacuolar H-ATPases (V-ATPases) are conserved ATP-dependent proton pumps that acidify intracellular compartments in eukaryotic cells. The role of Cpvma1, a V-ATPase catalytic subunit A of , was investigated by generating -overexpressing and -silenced strains. The mutant strains were evaluated for phenotypic characteristics, V-ATPase activity, response to elevated pH and Ca in the medium, virulence on chestnut, and accumulation of hypovirus RNA in the cells. Compared with the wild-type strain, -overexpressing strains showed no significant difference in phenotype; however, -silenced strains exhibited a phenotype of reduced growth rate, lower level of sporulation, and a marked decrease in V-ATPase activity and virulence. In addition, silencing of increased sensitivity to elevated pH and Ca, implicating an important role for Cpvma1 in pH adaptation and Ca homeostasis. Furthermore, silencing of resulted in significantly decreased accumulation of hypoviral RNA. Taken together, our results indicate that Cpvma1 plays an important role in the regulation of phenotypic traits and virulence and the accumulation of hypovirus RNA in .