Identification and temporal expression analysis of conserved and novel microRNAs in Sorghum

Sweet Sorghum is largely grown for grain production but also recently emerged as one of the model feedstock plants for biofuel production. In plants, microRNA (miRNA)-guided gene regulation plays a key role in diverse biological processes, thus, their identification in different plant species is essential to understand post-transcriptional gene regulation. To identify miRNAs in Sorghum, we sequenced a small RNA library. Sequence analysis revealed the identity of 29 conserved miRNA families. Importantly, 13 novel miRNAs are identified, seven of which are conserved in closely related monocots. Temporal expression analysis of conserved and novel miRNAs indicated differential expression of several miRNAs. Approximately 125 genes that play diverse roles have been predicted as targets and a few targets were experimentally validated. These results provided insights into miRNA-controlled processes in Sorghum and also laid the foundation for manipulating miRNAs or their targets for improving biomass production and stress tolerance in Sorghum.

► Identified 113 miRNAs belonging to 29 conserved miRNA families in Sorghum. ► Identified 13 novel miRNAs of which 7 are conserved in related monocots whereas 6 others are Sorghum-specific. ► Predicted 125 genes as targets for both conserved and newly identified miRNAs in Sorghum.