Heterosis, or enhancement through outbreeding, is one of the most promising approaches for increasing crop yield. Male sterility (MS), which promotes heterosis, has been widely applied in hybrid crop production. Medicago truncatula is a model legume species and is closely related to M. sativa, an important legume forage plant. Although the molecular mechanisms of MS in M. truncatula and M. sativa remain unclear, several studies of MS have been conducted in Arabidopsis thaliana.
MicroRNAs (miRNAs) are a class of non-coding endogenous negative regulators that regulate gene expression at both the transcriptional and post-transcriptional levels. However, little is known about the expression characteristics of miRNAs during pollen development in Brassica oleracea. In this study, five known and three novel miRNAs were identified and their expression patterns were compared in the flower buds of B. oleracea using stem-loop reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR.