Identification The Peroxidase Activities And Proteomics Of Different Genotype Rice Species Response To The Rice Blast Fungus

Rice blast, caused by Magnaporthe oryzae, is one of the most serious diseases of rice worldwide. The use of resistant cultivars is the most effective, economical and safe way to control this disease. Therefore, people are focused on the utilization of species with single and multiple resistances. In order to study the relationship of rice resistant to rice blast, susceptible rice germplasm Nipponbare and resistant germplasm Wuyunjing 7 were infected by M. oryzae, and the peroxidase activities and proteomics of the infected rice leaves were analyzed and identified.1. The activities of peroxidases were increased in the infected rice leavesThe activities of peroxidases, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) which scavenging reactive oxygen species (ROS), were increased in the infected rice leaves of both rice germplasms. The level of the antioxidants of malondialdehyde (MDA) and soluble protein content also increased. Especially in the susceptible germplasm Nipponbare, activities of peroxidases were significantly higher than the resistant materials. This may due to the stimulation of rice blast fungus, which breaks the balance of the redox system in plants, and caused an increased ROS in leaves. In order to kill the pathogens in the cells, lots of ROS produced in the plant cells, to maintenance the ROS balance in the cells, the activity of peroxidases (SOD, POD, CAT) increased to scavenge the ROS. At the same time, the accumulation of reactive oxygen species results in membrane lipid peroxidation, and increases the final product of membrane lipid peroxidation MDA. In addition, the stimulation of pathogen may inhibit the degradation of the protease or activate protein synthesis in vivo, which resulting in an increase of soluble protein content in the rice leaf cells. Disease-resistant rice germplasm has a strong resistance to disease; therefore, when subject to rice blast infection, the accumulation of ROS is relatively low in vivo. In contrast, the susceptible germplasm needs to increase the activities of peroxidases to scavenge the ROS. The results showed that the redox system plays an important role in the process of rice resistant to rice blast disease.2. The changes in proteomic level of rice induced by rice blastThe seedlings of susceptible rice germplasm Nipponbare and resistant rice germplasm Wuyunjing 7 were infected by conidial suspension from Huai’an’s local strain. The rice leaves were collected and the total proteins were extracted after 24 h,48 h and 72 h inoculation. The proteome changes were analyzed by an iTRAQ proteomics approach. Total 107 and 126 differentially expressed proteins were identified in Nipponbare and Wuyunjing 7, respectively. These identified proteins are involved in different biochemical responses and metabolic processes with obvious functional tendencies toward redox homeostasis, defense, signal transduction, protein metabolism, photosynthesis, carbohydrate/energy metabolism, amino acid metabolism and other unknown functions. The results will help us to better understand the mechanisms of the rice resistant to rice blast disease and will benefit to make novel strategies to control the disease. Since this is a basic research, further studies must be conducted to explore the molecular resistant mechanisms on the pathogen-plant interactions.