A pathogenesis-related protein 1 of Cucurbita moschata responds to powdery mildew infection.

Pumpkin ( Duch.) productivity is severely hindered by powdery mildew (PM) worldwide. The causative agent of pumpkin PM is , a biotrophic fungus. Pathogenesis-related protein 1 (PR1) homolog was previously identified from transcriptomic analysis of a PM-resistant pumpkin. Here, we investigated the effects of gene from pumpkin for resistance to PM. Subcellular localization assay revealed that is a cytoplasmic protein in plants. The expression of gene was strongly induced by inoculation at 48 h and exogenous ethylene (ET), jasmonic acid (JA) and NaCl treatments, but repressed by HO and salicylic acid (SA) treatments. Visual disease symptoms, histological observations of fungal growth and host cell death, and accumulation of HO in transgenic tobacco plants indicated that overexpression significantly enhanced the resistance to compared to wild type plants during PM pathogens infection, possibly due to inducing cell death and HO accumulation near infected sites. The expression of was significantly induced in transgenic tobacco plants in response to , suggesting that overexpression positively modulates the resistance to PM via the SA signaling pathway. These findings indicate that is a defense response gene in and can be exploited to develop disease-resistant crop varieties.