Expression Profiling Of Rice Post Infection Of Rice Blast Fungus By RNA-seq

Rice is one of the most important crops worldwide,while the rice blast disease caused by M. oryzae could reduce the yield, even completely destroy the rice field. Interaction between rice and rice blast follows gene-to-gene hypothesis which means the resistance(R) gene in rice interacts with avirulence(AVR) gene in the blast fungus triggering the resistance pathway. The R gene mediated resistance belongs to specific resistance that the variety carrying the R gene will lose resistance to the blast disease in several years after its releasing. The reseaches have demonstrated that the genes involved in plant resistance displayed broad spectrum resistance recently. Thus, the studies on those so called disease related genes will deeply understand the mechanism of rice resistance to the blast disease and also provide resource of the genes for breeding program.The rice variety Katy and its fast-neutron mutant M2354 carry the functional Pita gene which is supposed to confer rice resistance to the blast fungi containing the AVR-Pita gene. However, M2354 was extremely susceptible to the blast isolates containing the AVR-Pita gene, implying that the mutated gene in M2354 completely block the resistance signals transduction. RNA-seq was applied to investigate the differential expressed genes(DEGs) of Katy and M2354 post inoculation with the blast isolates C30. There were 686 DEGs in Katy and 1057 DEGs in M2354. Annotation to those DEGs manifested that most of the DEGs was similar and functional as kinases, oxidoreductases, cytochromes P450, receptor like proteins, transporters, pathogenesis genes, metabolic of sugers, synthesis of terpenoids and flavonoids, WRKY and MYB transcription factors and so on. Meanwhile, we noticed that gibberellin receptor was specific expressed in M2354 and RPM1 and NBS-LRR genes were specific expressed in Katy.The DEGs in Katy and M2354 were significantly enriched in 18 and 21 KEGG pathways, respectively. Eighteen pathways were shared between Katy and M2354, and 3 pathways including brassinosteroid biosynthesis, carotenoid biosynthesis and ascorbate and aldarate metabolism were specific to M2354.Fifty two and 101 alternative splicing events were detected by Tophat methods. To verify the alternative splicing, we tested gene expression of LOC_Os07g46852 by RT-PCR. Katy contained one or two transcripts while M2354 could have up to 4 transcripts, and the existence and expression level of the transcripts could depend on time post inoculation.In summary, the globle expression profiling of Katy and M2354 was studied using RNA-seq method. The results provided a reliable experimental and theoretical basis for revealing the mechanism of rice resistance to the blast disease andbreeding broad spectrum resistance varieties.