Overexpression of Poplar PtrWRKY89 in Transgenic Arabidopsis Leads to a Reduction of Disease Resistance by Regulating Defense-Related Genes in Salicylate- and Jasmonate-Dependent Signaling

• Published in: PloS one 2016-03, Vol.11 (3), p.e0149137
• Main Authors: Jiang, Yuanzhong, Guo, Li, Liu, Rui, Jiao, Bo, Zhao, Xin, Ling, Zhengyi, Luo, Keming
• Format: Article
• Language: English
• Subjects: Acids; Analysis; Arabidopsis; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biology and Life Sciences; Botrytis - pathogenicity; Chlorophyll - analysis; Crosstalk; Cyclopentanes - pharmacology; Disease Resistance; Down-Regulation - drug effects; Education; Genes; Genes, Reporter; Genetic aspects; Genetic engineering; Genomics; Hormones; Hydrogen Peroxide - metabolism; Jasmonates; Jasmonic acid; Laboratories; Leaves; Life sciences; Localization; Nuclei; Oxylipins - pharmacology; Pathogens; Phenotype; Plant defenses; Plant hormones; Plant Leaves - metabolism; Plant resistance; Plant sciences; Plants, Genetically Modified - genetics; Plants, Genetically Modified - growth & development; Plants, Genetically Modified - metabolism; Poplar; Promoter Regions, Genetic; Proteins; Pseudomonas syringae; Pseudomonas syringae - pathogenicity; Real-Time Polymerase Chain Reaction; Regulation; Reporter gene; Research and Analysis Methods; RNA, Plant - isolation & purification; RNA, Plant - metabolism; Salicylic acid; Salicylic Acid - pharmacology; Salicylic acids; Signal transduction; Signal Transduction - drug effects; Signaling; Transcription (Genetics); Transcription factors; Transcriptional Activation - drug effects; Transcriptome
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0149137

The plant hormones jasmonic acid (JA) and salicylic acid (SA) play key roles in plant defenses against pathogens and several WRKY transcription factors have been shown to have a role in SA/JA crosstalk. In a previous study, overexpression of the poplar WRKY gene PtrWRKY89 enhanced resistance to pathogens in transgenic poplars. In this study, the promoter of PtrWRKY89 (ProPtrWRKY89) was isolated and used to drive GUS reporter gene. High GUS activity was observed in old leaves of transgenic Arabidopsis containing ProPtrWRKY89-GUS construct and GUS expression was extremely induced by SA solution and SA+MeJA mixture but not by MeJA treatment. Subcellular localization and transactivation assays showed that PtrWRKY89 acted as a transcription activator in the nucleus. Constitutive expression of PtrWRKY89 in Arabidopsis resulted in more susceptible to Pseudomonas syringae and Botrytis cinerea compared to wild-type plants. Quantitative real-time PCR (qRT-PCR) analysis confirmed that marker genes of SA and JA pathways were down-regulated in transgenic Arabidopsis after pathogen inoculations. Overall, our results indicated that PtrWRKY89 modulates a cross talk in resistance to P. syringe and B. cinerea by negatively regulating both SA and JA pathways in Arabidopsis.