Overexpression of the Arabidopsis thaliana EDS5 gene enhances resistance to viruses

Abstract

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.

Activation tagging of ATHB13 in Arabidopsis thaliana confers broad-spectrum disease resistance

“…In 3221, up-regulation of PR1 may be associated with the enhanced expression of EDS5. It was demonstrated that overexpression of EDS5 leads to accumulation of SA, which can induce the expression of PR1 (Ishihara et al 2008). Also, elevated expression of PR1 may be modulated by WRKY or other transcription factors.…”

Salicylic Acid Biosynthesis and Metabolism

“…EDS5 shows homology to transporters of the MATE (Multidrug And Toxic compound Extrusion; Kuroda and Tsuchiya, 2009) family, which transport small organic molecules (Nawrath et al, 2002). Given EDS5's location in the chloroplast (Ishihara et al, 2008), it is possible that this protein regulates SA accumulation by controlling transport of specific molecules across the plastid membrane. One possibility is that EDS5 transports plastid-localized IC to the cytosol for subsequent conversion to SA.…”

The multidrug and toxic compound extrusion (MATE) family in plants

“…The Arabidopsis enhanced disease susceptibility 5 (eds5) mutant displayed impaired SA accumulation and reduced basal disease resistance (Nawrath et al 2002). In contrast, overexpression of AtEDS5 in Arabidopsis enhanced SA accumulation and resistance to viruses (Ishihara et al 2008). Recent genetic and biochemical analyses showed that this MATE transporter functioned in epidermal cells by exporting SA from its site of biosynthesis in the chloroplast to the cytosol (Serrano et al 2013;Yamasaki et al 2013).…”