ARS | Publication request: Dissecting Arabidopsis G beta signal transduction on the protein surface

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 16, 2012
Publication Date: July 1, 2012
Citation: Jiang, K., Frick-Chen, A., Trusov, Y., Delgado-Cerezo, M., Rosenthal, D.M., Lorek, J., Panstruga, R., Booker, F.L., Botella, J., Molina, A., Ort, D.R., Jones, A.M. 2012. Dissecting Arabidopsis G beta signal transduction on the protein surface. Plant Physiology. 159:975-983.

Interpretive Summary: This work is a proof of concept showing that it is possible to make directed changes on the protein surface of key plant signalling molecules to confer specific traits. The goal is to engineer crop plants by making highly specific changes rather than the more drastic approach of deleting and adding whole genes. Loss and gain of genes confers specific traits but most likely this is a mix of both good and bad, necessitating a new approach. The Arabidopsis signalling molecule Gbeta subunit (AGB1) plays important roles in plant development and responses to intrinsic and extrinsic stimuli. We identify key sites on the signal molecule surface which function as the unique recognition site between AGB1 and its targets. That is, we show that substitutions of single amino acid on the AGB1 interface allow distinguishing different roles of AGB1 among its multiple signaling functions.

Technical Abstract: The heterotrimeric G protein complex provides signal amplification and target specificity. The Arabidopsis Gbeta subunit of this complex (AGB1) interacts with and modulates the activity of target cytoplasmic proteins. This specificity resides in the structure of the interface between AGB1 and its targets. Important surface residues of AGB1, which were deduced from a comparative evolutionary approach, were mutated to dissect AGB1-dependent physiological functions. Analysis of the capacity of these mutants to complement well-established phenotypes of Gbeta-null mutants revealed AGB1 residues critical for AGB1-mediated specific biological processes, including growth architecture, pathogen resistance, gas exchange, and photosynthesis. These findings provide new information to direct finely-tuned engineering of crop yield and traits.