Dual inhibition of vacuolar ATPase subunit H and iron availability induces intrinsic apoptosis in Penicillium digitatum from citrus fruit

Abstract

The intracellular pH and iron homeostasis are essential for cell metabolic processes, which are important pathways to exploit novel antifungal targets. In this study, we evaluated the effects of simultaneously inhibition of vacuolar ATPase subunit H (VmaH) and iron availability on Penicillium digitatum and its action mode. Using RNA interference (RNAi) technology to silence the VmaH gene and treating the fungus with iron chelator ciclopirox coalmine (CPX), we found that the dual treatment inhibited the growth and pathogenicity of P. digitatum. Physiological and quantitative real-time PCR gene expression analysis indicated that this combination disrupted the pH and iron homeostasis within the fungal cells. Further results showed VmaH gene silencing combined with iron-chelation caused mitochondria dysfunction, endoplasmic reticulum (ER) stress, and an increase in reactive oxygen species (ROS) production. These effects led to the exacerbation of mitochondrial permeability transition pore (MPTP) opening, resulting in an increased release of calcium ion and cytochrome c from mitochondria. Consequently, there was an obvious regulation of apoptosis-related genes. Therefore, the combination of VmaH inhibition and iron chelation can induce intrinsic apoptosis in P.digitatum through ER stress-induced mitochondrial dysfunction, offering a novel strategy for the development of postharvest fungal pathogens control mechanisms.