Identification and Characterization of Verticillium nonalfalfae-responsive microRNAs in hops (Humulus lupulus L.)

Micro RNAs are 21 to 24 nucleotide long, non-coding RNA molecules that regulate gene expression at the post-transcriptional level. They can modulate various biochemical and physiological processes, including plant responses and resistance to fungal pathogens, by regulating the expression of numerous genes. In our study we identified miRNAs in hops and their expression patterns in the roots of susceptible and resistant hop cultivars in the early stage of infection with the fungus V. nonalfalfae. The roots of 3 biological replicates of one-year-old rooted cuttings of each cultivar were immersed for 10 minutes in a suspension containing conidia of the highly virulent strain of V. nonalfalfae (PV1, isolate T2), and the roots of 3 control plants of each cultivars were mock-inoculated using sterile water. Artificially inoculated (treated) and mock-inoculated (control) root tissue was sampled after 24 h post-inoculation. A total of 12 small RNA-seq libraries were sequenced using Ion Proton system.