Investigating the MicroRNAomes of Two Developmental Phases of Dendrocalamus latiflorus (Poaceae: Bambusoideae) Inflorescences

摘要

Plant microRNAs (miRNAs) play important roles in various developmental and physiological processes (e.g. seed germination, vegetative growth, flowering, seed production, and responses to abiotic or biotic stimuli) by targeting mRNAs for cleavage or translational repression at the post-transcriptional level. Bamboo flowering is an unusual physiological phenomenon relative to the typical graminaceous plants. In this study, we focused on the microRNAome of developing Dendrocalamus latiflorus inflorescences. Solexa high-throughput small RNA (sRNA) sequencing technology was used to sequence and quantify the miRNAs expressed during two phases of D. latiflorus flower development. A total of 118 conserved miRNAs and 47 novel miRNAs was identified in the developing flowers. The transcript levels of most of the miRNAs were similar between the two phases. However, five miRNAs showed distinct changes as the flowering developed, with the novel miRNA dla-miR18 in particular showing a large difference in transcript abundance between the two phases. Fifteen of the D. latiflorus miRNAs found in this study appeared likely to be specific to flower development. Moreover, 130 of the floral unigenes of D. latiflorus were determined to be putative targets of the miRNAs, and the miRNA cleavage sites of seven of these putative targets were validated by 5'-RACE. The results of this study provide the first broad survey of the microRNAomes of Bambusoideae and yield valuable insights into the potential roles of microRNAs in bamboo inflorescence development. Our findings represent a starting point for future functional research on the role of miRNA in the flower development in D. latiflorus and related species.