Unraveling the miRnome of Nicotiana rustica (Aztec tobacco) - A Genomewide computational assessment

MicroRNAs (miRNAs) are endogenous small non-coding RNAs, known as chief regulators for cellular growth and development in plants. Nicotiana rustica (N. rustica), also known as Aztec tobacco is the second most widely used lucrative crop for tobacco production across the globe. Since the miRNAs of Nicotiana rustica have never been reported, we employed a genome-wide computational approach which resulted in 101 potential candidates of miRNAs, belonging to 73 families, followed by stringent filtration criteria. Statistical analysis confirmed the occurrence of uracil as the dominant initial biased nucleotide base at 5 prime ends of mature miRNAs that may lead to a significant role in miRNA biogenesis and or miRNA mediated gene regulation. Due to unavailability of target sequences, the RNAseq data of N. rustica leaf, flower, stem, and root were retrieved, assembled de novo and concatenated into a clustered customized transcript dataset. The study validates miR160, miR393, miR397, miR403 & miR529 miRNAs and confirmed their targets through experimentally proven literature evidence. These miRNAs can modulate the biological role in transcription regulation, defense response, transporter activity, hormonal signaling and different protein kinase activities. Collectively, this study reports putative miRNAs and their role in Aztec tobacco development and stress response.