title: Differential expression of peach ERF transcriptional activators in response to signaling molecules and inoculation with Xanthomonas campestris pv. pruni.
abstract: Ethylene response factors (ERFs) are a large family of transcription factors (TFs) that have diverse functions in plant development and immunity. However, very little is known about the molecular regulation of these TFs in stone fruits during disease incidence. In the present study, we describe the identification of five peach ERFs (Pp-ERFs), aiming to elucidate their potential roles in defense against Xanthomonas campestris pv. pruni (Xcp), the causal agent of bacterial spot disease. The phylogenetic analysis along with sequence comparisons indicated that all Pp-ERFs are transcriptional activators belonging to groups IX and IIV ERFs. The transactivation capacity of these proteins was verified in vivo where they all induced the expression of the GUS reporter gene and in a GCC-dependent manner. The nuclear localization was also confirmed for two of these proteins, Pp-ERF2.b and Pp-ERF2.c, after their transient expression in onion epidermal cells. The induction kinetics of Pp-ERFs after inoculation with Xcp was determined by qRT-PCR. Except for Pp-ERF2.b, transcript levels of Pp-ERFs increased strongly and rapidly in the resistant 'Venture' compared to the susceptible 'BabyGold 5' cultivar after infection with Xcp. In contrast, the expression of Pp-ERF2.b was several-fold higher in the susceptible cultivar after bacterial infection. The expression of Pp-ERFs was also monitored after treating with signaling compounds; salicylic acid (SA) (1 mM), ethephon (1 mM) and methyl jasmonate (MeJA) (50 μM). Although the results generally emphasize the role of ethylene/jasmonic acid (ET/JA) signaling pathways in regulating the expression of Pp-ERFs, there was a coordination of the timing of ET/JA responses, suggesting compensatory rather than synergistic interactions between these pathways during defense against Xcp.
authors.affiliation: Department of Plant Agriculture, University of Guelph, 4890 Victoria Av. N., PO Box 7000 Vineland Station, ON L0R 2E0, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Sherif
authors.forename: I
authors.initials: I
authors.lastname: El-Sharkawy
authors.forename: G
authors.initials: G
authors.lastname: Paliyath
authors.forename: S
authors.initials: S
authors.lastname: Jayasankar
mesh_terms: D000085:Acetates / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology; D005030:Ethylenes / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D054883:Oxylipins / Q000494:pharmacology; D010935:Plant Diseases / Q000382:microbiology; D010937:Plant Growth Regulators / Q000494:pharmacology*; D057865:Plant Immunity; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D027861:Prunus / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D020156:Salicylic Acid / Q000494:pharmacology*; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016959:Xanthomonas campestris / Q000276:immunology* / Q000502:physiology
chemical_list: D000085:Acetates; D003517:Cyclopentanes; D005030:Ethylenes; D054883:Oxylipins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; C072239:methyl jasmonate; C036216:ethylene; D020156:Salicylic Acid