A core functional region of the RFP1 promoter from Chinese wild grapevine is activated by powdery mildew pathogen and heat stress

RING-fingerproteins (RFP) function as ubiquitin ligasesand play key roles in plant responses to biotic and abiotic stresses. However, little information is available on the regulation of RFP expression. Here, we isolate and characterize the RFP promotersequence from the disease-resistant Chinese wild grape Vitis pseudoreticulata accession Baihe-35-1. Promoter-GUS fusion assays revealed that defense signaling molecules, powdery mildewinfection, and heat stress induce VpRFP1 promoter activity. By contrast, the RFP1 promoterisolated from Vitis vinifera was only slightly induced by pathogen infection and heat treatment. By promoterdeletion analysis, we found that the −148 bp region of the VpRFP1 promoterwas the core functional promoterregion. We also found that, in Arabidopsis, VpRFP1 expressed under its own promoter activateddefense-related gene expression and improved disease resistance, but the same construct using the VvRFP1 promoterslightly improve disease resistance. Our results demonstrated that the −148 bp region of the VpRFP1 promoterplays a key role in response to pathogen and heat stress, and suggested that expression differences between VpRFP1 and VvRFP1 may be key for the differing disease resistance phenotypes of the two Vitis genotypes.