Protein kinase GCN2 mediates responses to glyphosate in Arabidopsis

[Background] The increased selection pressure of the herbicide glyphosate has played a role in the evolution of glyphosate-resistance in weedy species, an issue that is becoming a threat to global agriculture. The molecular components involved in the cellular toxicity response to this herbicide at the expression level are still unidentified. [Results] In this study, we identify the protein kinase GCN2 as a cellular component that fosters the action of glyphosate in the model plant Arabidopsis thaliana. Comparative studies using wild-type and gcn2 knock-out mutant seedlings show that the molecular programme that the plant deploys after the treatment with the herbicide, is compromised in gcn2. Moreover, gcn2 adult plants show a lower inhibition of photosynthesis, and both seedlings and adult gcn2 plants accumulate less shikimic acid than wild-type after treatment with glyphosate. [Conclusions] These results points to an unknown GCN2-dependent factor involved in the cascade of events triggered by glyphosate in plants. Data suggest either that the herbicide does not equally reach the target-enzyme in a gcn2 background, or that a decreased flux in the shikimate pathway in a gcn2 plants minimize the impact of enzyme inhibition. © 2015 Faus et al.; licensee BioMed Central.
This work was mainly supported by the Universidad Politecnica de Valencia (PAID2011-16) and the Ministerio Español de Ciencia y Tecnología (BFU2011-22526). The work was partially supported through a grant from the Ministerio Español de Ciencia y Tecnología (AGL-2010-18621). We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)