Establishment Of The Methods For Simultaneous Quantification Of Multiple Phytohormones And Metabolites In Rice And Identification Of Disease Resistance Mutant

Rice is one of the most important foods for the world population and half of the people live on rice in the world. Rice production is always threatened with plant disease, such as bacterial blight (BB), bacterial leaf streak (BLS) and blast fungus. Using the plant defence genes to improve the defence system of rice is the most efficient method to control diseases. So, understanding the mechanism of plant defence is very important in rice breeding. In this study, we developed the convenient and sensitive methods to quantification of multiple phytohormones using an ultra-performance liquid chromatography couple with tandem quadrupole mass spectrometry. The methods of quantification of multiple phytohormones and other function genome provide basis for understanding of the molecular mechanisms of rice defense responses.A convenient, sensitive, and reliable method was developed for simultaneous quantification of multiple phytohormones, abscisic acid, indole-3-acetic acid, jasmonic acid, and salicylic acid, hormone conjugates, IAA-aspartic acid, JA-isoleucine, and methyl jasmonate, and phytoalexins, momilactones A, naringenin, and sakuranetin. This method combines a convenient procedure for preparing crude extracted samples and a sensitive quantification assay using an reverse chromatography-tandem quadrupole mass spectrometry. Using this method, we present the dynamic profilings of defense-related phytohormones, hormone metabolites, and phytoalexins in rice interaction with Xanthomonas oryzae pv. oryzae (Xoo) that causes bacterial blight, one of the most devastating diseases of rice worldwide. These results provide a basis for understanding of the molecular mechanisms of rice defense responses.A method coupled with mixed SPE was developed for simultaneous quantification of CKs and GAs in rice. Using this method, we can simultaneous quantify indole-3-acetic acid, jasmonic, salicylic acid, abscisic acid, CKs, GA1and related metabolites. We present the dynamic profilings of CKs, GA1and other defense-related phytohormones, hormone metabolites in0.1g rice sample. So, we can quantify multiple phytohormones in the rice only with much less sample compared with preious reports. A powerfull tool was provided in understanding of the molecular mechanisms of rice defense responses and the procdure of plant hormone metabolism of rice growth and development.We identified40lession mimic mutant by screening the T-DNA insertion rice mutant pool in our Lab. The flank sequence of a lession mimic mutant named03Z11MP37is cosegagation with the mutant phenotype. We also isolate a disease resistance mutant named03Z11BB48and a susceptible mutant named04Z11QG04to Xoo compared with wild type. In04Z11QG04, the inserted T-DNA was inserted into intron between the16th and17thextron of gene named OsFBL52. The expression of OsFBL52was knockout in T-DNA insertion mutant. OsFBL52belongs to a large family and contain60members in rice genome at least, but their functions are poorly understood. After inoculation with Xoo and cosegregation analysis, the results showed that OsFBL52was a positive regulator of rice resistance to bacterial blight disease. Knockout of OsFBL52reduced resistance to Xoo and increased plant height in comparison with the wild type plants, a phenotype that mainly resulted from elongated internodes. Basal expression of several GA-related genes, including GA2ox, GA20ox, and Os30ox were upregulated in the mutant. These results suggest that OsFBL52mybe a positive regulator in rice disease resistance by.affect GA biosynsis.