Metabolic Research On The Interactions Between Rice And Fungi Based On Derivative GC-MS Analysis

Plants did not exist in natural world alone, while living with different kinds of micro-organism inside or outside. Plant-microbe interactions depend on the establishment of a nutritional interface allowing nutrient trafficking between plants and microbial symbionts or pathogens. The establishment and maintainment between plants and microbial symbionts or pathogens, leading to a inevitably metabolites qualitative change of the host itself, with a vital the influence on the growth and development of the plants directly or indirectly. Metabolomics, as a non-targeted method which is applied to describe the global changes of metabolites comprehensively. By analyzing the metabolites in plant tissues, we can know about responses of biological system to perturbations imposed by microbes in global.The fungus Harpophora oryzae, was first described among endophytes residing in domestic Chinese wild rice (Oryza granulate), could promote rice growth and biomass accumulation significantly. Phylogenetic analyses have shown that Harpophora has a close relationship to other members of the Magnaporthaceae, such as Magnaporthe oryzae. Based, on this, we choose two kinds of fungus, H. oryzae and M. oryzae to inoculate rice roots, using derivative GC-MS analysis method and pattern recognition, including principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA). The main results as follows:1) Construction of metabonomic sampling and GC-MS analysis system based on plant-microbe interactionBased on colonization characteristics between the two fungus and rice, a sampling method is established for metabonomics research, sampling process is elaborate, which can eliminate the interference of external environment factors; According to the references and improvements of previous studies, a suitable analysis method of plant metabolomics was set up. Chemometrics methods, such as PCA, PLS-DA also used to ananlyze changes of metabolites of rice roots in different periods inoculated with two fungus, combined with metabolic pathways based on present researches. 2) Exhibiting the fungal infection process based on fluorescence stereomicroscopyBased on fluorescence stereomicroscopy, we observed the infection process of two fugus in different period, showing the colonization characteristic. The infection process is similar in early period, including the conidium germination, the infection and shuttle of hypha in plant cells. In middle and anaphasis infection period, M. oryzae penrtrated into column and vascular tissue, while the H. oryzae stoped within the cortex, without infecting the column cells and vascular tissue.3) The metabolite change of two different interaction systemBased on the metabonomics method set up in previous, single comparison of the samples in different infection period and overall analysis were conducted, significant metabolites were found. The result showed that:in early infection process, the metabolic pattern of the host is similar, involving defense responses, the supplyment of carbohydrate, amino acids metabolic pathways and shikimic acid pathway. Shikimic acid pathway to produce excess shikimic acid and quinic acid still exist in the roots inoculated with M. oryzae. However, shikimic acid pathway was no longer activated in the later infection period in the roots inoculated with H. oryzae.4) The affect on aerial part of rice by the infection of two fungusH. oryzae, colonized in the roots of rice, could not spread to the ground by microtubule system, without causing the metabolic changes of the aerial in early and middle period. Just after successful colonization in the roots, the significant biological effects were characterized. In contrast, M. oryzae, as a system infection fungi, the infection process is fierce, causing the metabolic changes of aerial part, and mainly involves the primary metabolic pathways.