Overexpression of pumpkin CpVQ30 increased susceptibility of tobacco to powdery mildew

Powdery mildew stands out as a prominent disease in Cucurbita pepocultivation, characterized by its widespread distribution, high incidence rates, and a substantial impact on yield. In severe cases, production cuts can be as high as 50 %.The VQ proteins serve as auxiliary proteins capable of interacting with WRKY transcription factors and mitogen-activated protein kinase (MAPK).They play a pivotal role in mediating plant responses to both biotic and abiotic stresses.In this study,we found that the C. pepo protein CpVQ30（XP_022953968.1）was down-regulated in disease-resistant material F2 and up-regulated in disease-susceptible material M3 after powdery mildew infection and hormone treatments. Compared to the wild-type(WT) tobacco plants, transgenic lines overexpressing CpVQ30 (OE) exhibited a more severe incidence of powdery mildew.The activites of superoxide dismutase (SOD)、peroxidase (POD) were reduced, while the contents of reactive oxygen species (ROS),and the lipid peroxidation marker malondialdehyde (MDA) were increased. Additionally, powdery mildew mycelium exhibited accelerated growth and accumulation.The expression levels of defense-related genes were reduced after powdery mildew infection.CpVQ30 enhances tobacco susceptibility to powdery mildew.