Theoretical Model of the Three-dimensional Structure of a Disease Resistance Gene Homolog Encoding Resistance Protein in Vigna mungo

Abstract

Plant disease resistance (R) genes, the key players of innate immunity system in plants encode ‘R’ proteins. ‘R’ protein recognizes product of avirulance gene from the pathogen and activate downstream signaling responses leading to disease resistance. No three dimensional (3D) structural information of any ‘R’ proteins is available as yet. We have reported a ‘R’ gene homolog, the 'VMYR1′, encoding ‘R’ protein in Vigna mungo. Here, we describe the homology modeling of the 'VMYR1′ protein. The model was created by using the 3D structure of an ATP-binding cassette transporter protein from Vibrio cholerae as a template. The strategy for homology modeling was based on the high structural conservation in the superfamily of P-loop containing nucleoside triphosphate hydrolase in which target and template proteins belong. This is the first report of theoretical model structure of any ‘R’ proteins.     

Modeling spatiotemporal dynamics of vole populations in Europe and America

The mathematical models proposed and studied in the present paper provide a unified framework to understand complex dynamical patterns in vole populations in Europe and North America. We have extended the well-known model provided by Hanski and Turchin by incorporating the diffusion term and spatial heterogeneity and performed several mathematical and numerical analyses to explore the dynamics in space and time of the model. These models successfully predicted the observed rodent dynamics in these regions. An attempt has been made to bridge the gap between the field and theoretical studies carried out by Turchin and Hanski (1997) [23] and Turchin and Ellner (2000) [24]. Simulation experiments, mainly two-dimensional parameter scans, show the importance of spatial heterogeneity in order to understand the poorly understood fluctuations in population densities of voles in Fennoscandia and Northern America. This study shed new light upon the dynamics of voles in these regions. The nonlinear analysis of vole data suggests that the dynamical shift is from stability to chaos. Diffusion driven model systems predict a new type of dynamics not yet observed in the field studies of vole populations carried out so far. This has been termed as chaotic in time and regular in space (CTRS). We observed CTRS dynamics in several simulation experiments. This directs us to expect that dynamics of this animal would be de-correlated in time and simultaneously mass extinctions might be possible at many spatial locations.