Differential Proteomic Analysis In Allelopathy Rice Accessions Exposed To Different Nitrogen Supplies

The allelopathy effect are due to inhibitory substances that are released directly or indirectly from living plants (donor) into the environment through root exudation, leaching, volatilization and residual decomposition of the donor plant. These phytotoxic substances are termed as allelochemicals. The partential of allelopathy has been a particularly intense study area of ecology and environment science.Numerous research indicated that the content of phenolic acid in the herbaceous and wood plants increased in the environment stress. Because when plant exudated chemicals to environment, root is more directly contact with soil, water and received plant such as barnyardgrass(BYG), the changes of root protein would be more sensitive. We regard rice root as a main research boject to discover the molecular mechanism responding to different stresses in allelopathic and nonallelopathic rice accessions by using differential proteomics and bioinformatics as a tool. The expriment composed of two N supplies (1N,20mg/L,1/4N, 5mg/L) and two desities of barnyardgrass (rice:BYG=35:5,rice:BYG=40:0). After treatment for 7 days, we extracted the protein in two treatments with two level. Then two-dimensional gel electrophoresis (2-DE) of the proteins was performed. Image analysis revealed about 1000-1200 protein spots on each 2-DE gel after stained with silver nitrate.It was found that 45 proteins expressed differentially in different treatments, forty-three proteins were identified by MALDI-TOF/MS and database searching. These proteins were divided into 4 catagories : defense, signal transduction, metabolism and protein stabilization. The composition of proteins in the two rice accessions PI312777 ( allelopathy) and Lemont (nonallelopathy) is almost the same, each of them has a complex resistant signal transduction and metabolic regulative network, and the physicochemical properties were charactierized by the proteins showing differential expression pattern. The abudance of resistent and defensive proteins increased significantly with the environment stress enhancing, which could be considered the properties of molecular ecology in allelopathic rice.Several resistent-related proteins were also found in this research, after evaluating, we considered they might be the key resistent proteins accomplished with allelopathy. Accordingly, 3D structure of the key proteins and its function were predicted and further analysed. The result would provide helpful information to our further research on molecular cloning. Finally,the existing problems and the direction to further study were discussed in the paper.