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

• Published in: Frontiers in genetics Vol. 14; p. 1168138
• Main Authors: Guo, Wei-Li, Yang, He-Lian, Zhao, Jin-Peng, Bian, Shi-Jie, Guo, Yan-Yan, Chen, Xue-Jin, Li, Xin-Zheng
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 01-08-2023
• Subjects: Cucurbita moschata; functional analysis; Genetics; powdery mildew; PR-1; transgenic tobacco
• ISSN: 1664-8021; 1664-8021
• DOI: 10.3389/fgene.2023.1168138

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