MicroRNAs (miRNAs) are small non-coding RNAs about 20-24 nucleotides long, playing regulatory role. The conserved nature among the various organisms makes them a good source of new miRNAs discovery by comparative genomics approach using bioinformatic tools. A systematic search approach was used for inter-species homologs of miRNA precursors (pre-miRNAs), from known Helianthus expressed sequence tags (ESTs). The study resulted in 61 novel miRNAs belonging to 34 families from Helianthus ESTs. The 28 miRNA families; mir 159,160, 164, 170, 390, 393, 413, 415, 419, 426, 446, 530, 822, 842, 846, 1310, 1888, 2086, 2657, 2667, 2678, 2659, 2911, 2938, 3440, 3521, 3623, and 3630 are reporting for the first time in Helianthus. In the 61 new miRNAs, 20 are from H. tuberosus, 17 miRNAs belong to H. annus, 8 are from H. ciliaris, 5 to H. exilis, 4 is from H. argophyllous, H. petiolaris each and 3 are from H. paradoxus. All the pre-miRNAs form stable minimum free energy (mfe) stem-loop structure as their orthologues form and the mature miRNAs reside in the stem portion of the stem-loop structures. Their targets consist of growth and development related, transcription factors, signalling pathway kinases, stress resistant proteins and transport related proteins.

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MicroRNAs (miRNAs) are small, 18-26 nucleotides long, non-coding RNAs that play role in post-transcriptional gene regulation. Many of these are evolutionarily conserved. This suggests a powerful approach to predict new miRNAs in other species. In this research, structural and functional approaches were combined to make computational prediction of potential miRNAs and their targets in Bean (Phaseolus). Total 55 novel miRNAs were detected from 38 miRNAs families in Bean (Phaseolus). These families are; miR156, 160, 164, 168, 170, 171, 172, 319, 393, 396, 397, 398, 408, 414, 438, 444, 535, 1310, 1424, 1426, 1848, 1860, 1863, 2055, 2091, 2093, 2094, 2102, 2103, 2105, 2864, 2866, 2925, 2926, 4221, 4245, 4246 and 4250. In the 55 putative miRNAs; 28 miRNAs belong to Phaseolus acutifolius, 23 to Phaseolus vulgaris, 4 to Phaseolus coccineus. All the mature miRNAs reside in the stem portion of the hairpin structures. Total 146 potential protein targets were predicted for these miRNAs.