[Identification of miR160 family and their target genes in Rehmannia glutinosa in response to endophytic fungus GG22 infection].

ABSTRACT

This study aims to reveal the possible role of miR160 family in Rehmannia glutinosa in response to the infection of endophytic fungus Fusarium oxysporum GG22. Specifically, miR160 precursors and mature miR160 were retrieved from the small RNA database yielded by high-throughput sequencing. RNAfold was used to analyze the precursor structure, and DNAMAN and MEGA to analyze conservation and evolution of miR160 precursors and mature miR160. The target genes of miR160 were predicted and annotated, and the interaction was analyzed. Based on degradome sequencing, the target genes were further identified. The results showed that miR160 precursors had intact stem-loop structures. The precursor and mature sequences were conserved, particularly the 3 rd-16 th bases of the 5'-terminal. According to the phylogenetic tree, R. glutinosa had close evolutionary relationship with Arabidopsis thaliana, Oryza sativa, Salvia miltiorrhiza, and Sesamum indicum. A total of 22 target genes of miR160 were predicted and most of them were auxin response factor(ARF) genes. The target genes were involved in the Gene Ontology(GO) terms of biological processes, cellular components, and molecular functions. According to the degradome sequencing results, four target genes of miR160 were ARF(ARF18, ARF22) genes. R. glutinosa regulated its growth in response to the infection of endophytic fungus by changing the expression of miR160 and the target genes. qRT-PCR result of the differentially expressed rgl-miR160a and rgl-miR160a-3p was consistent with the sequencing result. This study clarifies the molecular mechanism of R. glutinosa in response to GG22 stress, laying a theoretical basis for the improvement and future research of R. glutinosa.