Differentied Expression Analysis Of MicroRNA In Banana Induced By Fusarium Oxysporum F.sp.cubense Tropical Race 4

MicroRNAs (miRNAs) are a class of small noncoding RNA molecules with the length of 18-25 nucleotides. MiRNA regulates target genes at the post-transcriptional level, which action modes depend on the complementation between miRNA and mRNA sequence of target genes. MiRNA has high regulation efficiency in target gene expression with higher speed than coding genes, which was not influenced by translation process. It plays an important role in plant growth and development, stress condition and epigenetic inheritance.In this study, using miRNA sequencing and degradome sequencing technologies,4 miRNA libraries and 4 degradome libraries were established sampling in different pathogen induced stages with Brazil banana and Fusarium oxysporum f.sp. cubense race 4 as genetic materials. Analyzing with bioinformatics, the known miRNA and candidate miRNA related to banana pathological reaction were gotten, and the expression profile at different pathogen induces stages was established, in which the corresponding target genes were determined. And the results were verified with qRT-PCR. They were transferred into Arabidopsis thaliana to be transgenic plants with the floral-dip method.1. There were 4 miRNA libraries, Banana CK、Banana 4h、Banana 24h、Banana 6d, using miRNA high-throughput sequencing technology, in which the reads number respectively were 16013204、16551770、17733937和18429778, and the number of clean reads respectively were 15795656、16359862、17492456、18056899 after removing linkers, contamination and poly A.2. After sequence comparison to precursor and maturity of miRNA for some certain scope in clean reads and miRBase,1220 known miRNA and 443 candidate miRNA. There are significantly different miRNA, which were chosen suing TPM and significant difference coefficient.3. After degradome sequencing, the number of total tags respectively were 19376180、20031339、19529695 and 20425417 in each libraries, and the number of clean tags respectively were 19181680、19934653、19436497 and 20327782 after preprocess.4. Identifying cleavage sites of miRNA,1288 target genes corresponding miRNA, 975 known miRNA and 313 candidate miRNA, were determined according to degradome sequencing.5.20 miRNA were chosen randomly to verify the authenticity of sequencing results using qRT-PCR.6. There are 8 important miRNA about pathological reaction according to gene ontology (GO) functional significant enrichment analysis and pathway significant enrichment analysis (KEGG), and overexpression vectors were built.7. The precursors of the miRNA were predicted using mfold software, which were related to stem-and-loop structure, and the lengths of them were 112-225 bp. The maturities of most of miRNA were from the 5’end of precursors.