Comparative Proteomics Study On Resistance To Phytophthora Sojae In Soybean

Phytophthora root and stem rot (PRR) caused by Phytophthora sojae M. J. Kaufmann&. J. W. Gerdemann (P. sojae), is one of the most devastating diseases in soybean [Glycine max (L.) Merr.] throughout soybean-growing regions all over the world. In China, P. sojae mainly exists in three soybean ecological regions including the Northeast region, the Huang-Huai-Hai region and the Southern region, and induces loss in yield and seed quality in main soybean production regions. Utilization of resistant varieties is the most economical and environmentally safe method for controlling this disease.Protein is the physiological functions of the executive, and is also a direct manifestation of the phenomenon of life. The study of protein structure and function will directly clarify the mechanism of the change of life. Transcription levels only to a certain extent reflect the changes in product of gene expression, but the real function of the protein is formed, which need go through the steps of post-transcriptional processing, translation regulation and post-translational processing and regulation and so on. Thus, proteomics has been widely used in the study of plant functional genomics.Using proteome, protein expression profiling and function of the differentially expressed proteins identified was analyzed in soybean-P. sojae interaction in this study. The main aims of this study were:(1) to mine the proteins involved in resistance-related P. sojae on the protein expression levels,(2) to further investigate the metabolic pathways of these proteins involved in the interaction of soybean-P. sojae,(3) to discover molecular mechanism of reisistance to P. sojae. The main results were as follows:1-Proteomics study of changes in soybean lines resistant and sensitive to P. sojaeUsing the hypocotyl inoculation technique, proteomics study of changes in soybean resistant Yudou25and sensitive NG6255to P. sojae strain PNJ1was analyzed. In the present study,46differentially expressed proteins were identified in soybean hypocotyls infected with P. sojae, using two-dimensional electrophoresis and matrix-assisted laser desorption/ionization tandem time of flight (MALDI-TOF/TOF). The expression levels of26proteins were significantly affected at various time points in the tolerant soybean line, Yudou25,(12up-regulated and14down-regulated). In contrast, in the sensitive soybean line, NG6255, only20proteins were significantly affected (11up-regulated and9down-regulated). Among these proteins,26%were related to energy regulation,15%to protein destination and storage,11%to defense against disease,11%to metabolism,9%to protein synthesis,4%to secondary metabolism, and24%were of unknown function.2. Proteomics analysis of soybean roots, hypocotyls and leaves under different treatmentsUsing2-DE and MALDI-TOF/TOF, proteomics study of soybean roots, hypocotyls and leaves under different treatments of SA, MeJA, ACC, H2O2, SNP, VB1and P. sojae was analyzed. Xinyixiaoheidou was susceptible to P. sojae strain P6497. These findings were as follows:(1)35differently expressed proteins were identified from soybean roots by MALDI/TOF-TOF. Among these proteins,23%were relative to disease/defense and secondary metabolism, respectively;17%to energy, followed with protein synthesis, protein destination and storage, transcription and metabolism, and3%were of cell structure and signal transduction, respectively, and8%with unknown function. The proteins involved in secondary metabolism were relative to the biosynthesis of ethylene, jasmonic acid and flavonoids.(2)58differently expressed proteins were identified from soybean hypocotyls by MALDI/TOF-TOF. Among these58proteins,41%were relative to energy and metabolism,12%to disease/defense and secondary metabolism, respectively,10%to protein destination and storage,7%to signal transduction and transcription, respectively,4%to cell structure,2%were of protein synthesis and transporters, respectively.(3)21differently expressed proteins were idedtified from soybean leaves by MALDI-TOF/TOF. The21identified proteins involved in energy dominated62%, reapectively. Those involved in secondary metabolism, protein synthesis and metabolism categories followed. The proteins relative to energy involved in the process of photosynthesis and respiration.3. iTRAQ-based protein profile analysis of soybean roots in response to P. sojae inoculationUsing the slant board technique, iTRAQ-based protein profile of soybean roots to P. sojae was analyzed. Su88-M21was resistant to P. sojae strain Pml4. A total of2136proteins were identified and a subset of280proteins was differentially expressed infected with P. sojae. Among of these280proteins, the proteins relative to defense against disease dominated16%,14%involved in protein destination and storage,12%involved in metabolism,11%to energy and protein synthesis, respectively,8%to signal transduction,6%involved in transporter and secondary metabolism, respectively,4%to cell structure. The last is relative to cell growth/division, only accounting for1%, and9%were of unknown function. The signal of jasmonid acid, ethylene, auxin and ubiquitin proteasome system is involved in the resistant mechanism of soybean to P. sojae.