Small RNA and Degradome Deep Sequencing Reveals Peanut MicroRNA Roles in Response to Pathogen Infection

摘要

Bacterial wilt (BW) disease is a widespread disease in peanut (Arachis hypogaea L.), reducing peanut production because of high susceptibility of most cultivated species. However, Arachis glabrata, a perennial wild relative, has high resistance to soil-borne diseases. MicroRNAs (miRNAs) have been characterized as important factors in plant growth, development, and biotic/abiotic stress responses. However, their roles in response to pathogen are still unknown in peanut. Here, we constructed four miRNA libraries from A. hypogaea and A. glabrata and identified 155 known miRNAs, 31 novel miRNAs, and 173 plausible candidates of novel miRNAs. After infected with BW, the expression of many known miRNA was induced or inhibited in both cultivated and wild-type peanuts. Many miRNAs displayed differential expression patterns in these two species, and the expression of some miRNAs was confirmed by quantitative real-time PCR (qRT-PCR) analysis. A total of 309 targets were predicted, among which 74 of them were confirmed by degradome sequencing. More than 10 of the targets were defense response genes, such as hypersensitive-induced response protein, leucine-rich repeat (LRR) receptor-like serine/threonine-protein kinase, GRAS, aquaporin, lipid transfer protein, ARF, MYB transcription factors, and MLP-like protein. Our results indicate that diverse set of miRNAs of cultivated and wild peanut species is responsive to BW infection and suggests a possible role in peanut disease resistance.