Overexpression of the Arabidopsis thaliana EDS5 gene enhances resistance to viruses

• Published in: Plant biology (Stuttgart, Germany) Vol. 10; no. 4; pp. 451 - 461
• Main Authors: Ishihara, T., Sekine, K.-T., Hase, S., Kanayama, Y., Seo, S., Ohashi, Y., Kusano, T., Shibata, D., Shah, J., Takahashi, H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-07-2008
• Subjects: Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis - virology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis Proteins - physiology; Basal resistance; Blotting, Northern; CMV resistance gene RCY1; Cucumovirus - growth & development; EDS5; Gene Expression Regulation, Plant; Immunity, Innate - genetics; MATE transporter; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Membrane Transport Proteins - physiology; Plant Diseases - genetics; Plant Diseases - virology; Plants, Genetically Modified - genetics; Plants, Genetically Modified - virology; PR-1a; Reverse Transcriptase Polymerase Chain Reaction; SA-dependent signal transduction; Salicylic Acid - metabolism; Serine-Arginine Splicing Factors
• ISSN: 1435-8603; 1438-8677
• DOI: 10.1111/j.1438-8677.2008.00050.x

The Arabidopsis thaliana ENHANCED DISEASE SUSCEPTIBILITY 5 gene (EDS5) is required for salicylic acid (SA) synthesis in pathogen-challenged plants. SA and EDS5 have an important role in the Arabidopsis RCY1 gene-conferred resistance against the yellow strain of Cucumber mosaic virus [CMV(Y)], a Bromoviridae, and HRT-conferred resistance against the Tombusviridae, Turnip crinkle virus (TCV). EDS5 expression and SA accumulation are induced in response to CMV(Y) inoculation in the RCY1-bearing ecotype C24. To further discern the involvement of EDS5 in Arabidopsis defence against viruses, we overexpressed the EDS5 transcript from the constitutively expressed Cauliflower mosaic virus 35S gene promoter in ecotype C24. In comparison to the non-transgenic control, the basal level of salicylic acid (SA) was twofold higher in the 35S:EDS5 plant. Furthermore, viral spread and the size of the hypersensitive response associated necrotic local lesions (NLL) were more highly restricted in CMV(Y)-inoculated 35S:EDS5 than in the non-transgenic plant. The heightened restriction of CMV(Y) spread was paralleled by more rapid induction of the pathogenesis-related gene, PR-1, in the CMV(Y)-inoculated 35S:EDS5 plant. The 35S:EDS5 plant also had heightened resistance to the virulent CMV strain, CMV(B2), and TCV. These results suggest that, in addition to R gene-mediated gene-for-gene resistance, EDS5 is also important for basal resistance to viruses. However, while expression of the Pseudomonas putida nahG gene, which encodes the SA-degrading salicylate hydroxylase, completely suppressed 35S:EDS5-conferred resistance against CMV(Y) and TCV, it only partially compromised resistance against CMV(B2), indicating that SA-dependent and -independent mechanisms are associated with 35S:EDS5-conferred resistance against viruses.