AUTHOR=Guo Wei-Li , Yang He-Lian , Zhao Jin-Peng , Bian Shi-Jie , Guo Yan-Yan , Chen Xue-Jin , Li Xin-Zheng 

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

JOURNAL=Frontiers in Genetics

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2023.1168138

DOI=10.3389/fgene.2023.1168138

ISSN=1664-8021

ABSTRACT=<p>Pumpkin (<italic>Cucurbita moschata</italic> Duch.) productivity is severely hindered by powdery mildew (PM) worldwide. The causative agent of pumpkin PM is <italic>Podosphaera xanthii</italic>, 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 <italic>CmPR1</italic> gene from pumpkin for resistance to PM. Subcellular localization assay revealed that <italic>CmPR1</italic> is a cytoplasmic protein in plants. The expression of <italic>CmPR1</italic> gene was strongly induced by <italic>P. xanthii</italic> inoculation at 48 h and exogenous ethylene (ET), jasmonic acid (JA) and NaCl treatments, but repressed by H<sub>2</sub>O<sub>2</sub> and salicylic acid (SA) treatments. Visual disease symptoms, histological observations of fungal growth and host cell death, and accumulation of H<sub>2</sub>O<sub>2</sub> in transgenic tobacco plants indicated that <italic>CmPR1</italic> overexpression significantly enhanced the resistance to <italic>Golovinomyces cichoracearum</italic> compared to wild type plants during PM pathogens infection, possibly due to inducing cell death and H<sub>2</sub>O<sub>2</sub> accumulation near infected sites. The expression of <italic>PR1a</italic> was significantly induced in transgenic tobacco plants in response to <italic>G. cichoracearum</italic>, suggesting that <italic>CmPR1</italic> overexpression positively modulates the resistance to PM via the SA signaling pathway. These findings indicate that <italic>CmPR1</italic> is a defense response gene in <italic>C. moschata</italic> and can be exploited to develop disease-resistant crop varieties.</p>