Humidity assay for studying plant-pathogen interactions in miniature controlled discrete humidity environments with good throughput

This paper reports a highly economical and accessible approach to generate different discrete relative humidity conditions in spatially separated wells of a modified multi-well plate for humidity assay of plant-pathogen interactions with good throughput. We demonstrated that a discrete humidity gradient could be formed within a few minutes and maintained over a period of a few days inside the device. The device consisted of a freeway channel in the top layer, multiple compartmented wells in the bottom layer, a water source, and a drying agent source. The combinational effects of evaporation, diffusion, and convection were synergized to establish the stable discrete humidity gradient. The device was employed to study visible and molecular disease phenotypes of soybean in responses to infection by Phytophthora sojae, an oomycete pathogen, under a set of humidity conditions, with two near-isogenic soybean lines, Williams and Williams 82, that differ for a Phytophthora resistance gene (Rps1-k). Our result showed that at 63% relative humidity, the transcript level of the defense gene GmPR1 was at minimum in the susceptible soybean line Williams and at maximal level in the resistant line Williams 82 following P. sojae CC5C infection. In addition, we investigated the effects of environmental temperature, dimensional and geometrical parameters, and other configurational factors on the ability of the device to generate miniature humidity environments. This work represents an exploratory effort to economically and efficiently manipulate humidity environments in a space-limited device and shows a great potential to facilitate humidity assay of plant seed germination and development, pathogen growth, and plant-pathogen interactions. Since the proposed device can be easily made, modified, and operated, it is believed that this present humidity manipulation technology will benefit many laboratories in the area of seed science, plant pathology, and plant-microbe biology, where humidity is an important factor that influences plant disease infection, establishment, and development

Journal of Proteomics & Bioinformatics- Open Access www.omicsonline.com Research Article JPB/Vol.2/August 2009 In Silico Identification of Putative Proton Binding Sites of a Plasma Membrane H +-ATPase Isoform of Arabidopsis Thaliana, AHA1

jpb.1000095 Copyright: © 2009 Kumar S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The plasma membrane potential and secondary transport systems in all eukaryotes are energized by the activity of P-type ATPase membrane proteins: H + ATPase (the proton pump) in plants and fungi and Na +, K +- ATPase (the sodium-potassium pump) in animals. The overall shape of proton pumps has been revealed by electron microscopy. The crystal structure of AHA2, a plasma membrane H +-ATPase isoform of Arabidopsis thaliana, by X-ray crystallography at 3.6 Å was available. The isoform is expressed mainly in root. In the present study homology modeling along with transmembrane topology predictions has been used to build the atomic model of AHA1, another plasma membrane H +-ATPase isoform of Arabidopsis thaliana expressing in both root and shoot. AHA2 was used as the template. The homology modeling was done using the MODELLER9v2 software. The model energy was minimized by applying molecular mechanics method. The root mean square deviation (RMSD) for C

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