Elucidating the functional role of predicted miRNAs in post-transcriptional gene regulation along with symbiosis in Medicago truncatula

Abstract Non-coding RNAs (ncRNAs) are found to be important regulator of gene expression because of their ability to modulate post-transcriptional processes. microRNAs are small ncRNAs which inhibit translational and post-transcriptional processes whereas long ncRNAs are found to regulate both transcriptional and post-transcriptional gene expression. Medicago truncatula is a well-known model plant for studying legume biology and is also used as a forage crop. In spite of its importance in nitrogen fixation and soil fertility improvement, little information is available about Medicago ncRNAs that play important role in symbiosis. To understand the role of Medicago ncRNAs in symbiosis and regulation of transcription factors, we have identified novel miRNAs and tried to establish an interaction model with their targets. 149 novel miRNAs are predicted along with their 770 target proteins. We have shown that 51 of these novel miRNAs are targeting 282 lncRNAs. We have analyzed the interactions between miRNAs and their target mRNAs as well as their targets on lncRNAs. Role of Medicago miRNAs in the regulation of various transcription factors were also elucidated. Knowledge gained from this study will have a positive impact on the nitrogen fixing ability of this important model plant, which in turn will improve the soil fertility.