Structural and biochemical characterisation of plant EDS1 disease resistance regulatory complexes
Final Report Abstract
In plants, EDS1 is a positive regulator of innate immunity against a wide range of pathogens. Although EDS1 and its sequence-related binding partners PAD4 and SAG101 share homology to eukaryotic lipases, enzymatic activity is dispensable for their immune signalling functions. We resolved the crystal structure of EDS1 as a soluble heterodimer with SAG101. This revealed that the N-terminal EDS1 domain is indeed highly related to lipases, including a structurally conserved Serine-Histidine-Aspartate catalytic triad. We therefore intensified efforts to examine the role of this lipase-related domain in EDS1 signalling. Experiments performed in planta and with recombinant proteins show that hydrolytic activity of EDS1 is not necessary for its function. However, binding of a lipidrelated molecule is possible and is being explored further in structure-function and ligand docking experiments. While the biochemical functions of EDS1, PAD4 and SAG101 remain elusive, substantial progress was made in understanding the roles of different EDS1 complexes in the innate immune response. Data suggest that molecular transitions of EDS1 between complexes containing PAD4 or SAG101 condition a multi-branched defense system. Analysis of the EDS1/SAG101 complex structure and molecular transitions is being continued in SFB 635 (Posttranscriptional control of protein function).
Publications
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(2010). Roles of Arabidopsis patatin-related phospholipases A in root development are related to auxin responses and phosphate deficiency. Mol. Plant 3:524-538
Rietz, S., Dermendjiev, G., Oppermann, E., Tafesse, F.G., Effendi, Y., Holk, A., Parker, J.E., Teige, M. and Scherer, G.F.
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(2010). Salicylic acid antagonism of EDS1-driven cell death is important for Arabidopsis immune and oxidative stress responses. Plant J. 62: 628-640
Straus, M.R., Rietz, S., ver Loren van Themat, E., Bartsch, M. and Parker, J.E.
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(2011). Crystallization and preliminary crystallographic analysis of Arabidopsis thaliana EDS1, a key component of plant immunity, in complex with its signalling partner SAG101. Acta Crys Sect F. 67:245-8
Wagner S, Rietz S, Parker JE, Niefind K
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(2011). Different roles of Enhanced Disease Susceptibility1 (EDS1) bound to and dissociated from Phytoalexin Deficient4 (PAD4) in Arabidopsis immunity. New Phytol. 191:107-19
Rietz S, Stamm A, Malonek S, Wagner S, Becker D, Medina-Escobar N, Vlot AC, Feys BJ, Niefind K, Parker JE
