Have you head of
Targetfinder? This tool predicts small RNA (i.e., microRNAs [miRNAs] and siRNAs) as guides for posttranscriptional and epigenetic regulation.
Project URLhttp://carringtonlab.org/resources/targetfinderReferencesAllen, E., Xie, Z., Gustafson, A. M., & Carrington, J. C. (2005). microRNA-directed phasing during trans-acting siRNA biogenesis in plants. Cell, 121, 207–221. doi:10.1016/j.cell.2005.04.004
Fahlgren, N., Howell, M. D., Kasschau, K. D., Chapman, E. J., Sullivan, C. M., Cumbie, J. S., … Carrington, J. C. (2007). High-throughput sequencing of Arabidopsis microRNAs: Evidence for frequent birth and death of MIRNA genes. PLoS ONE, 2(2). doi:10.1371/journal.pone.0000219
Recent publicationZhang, X., Niu, D., Carbonell, A., Wang, A., Lee, A., Tun, V., … Jin, H. (2014). ARGONAUTE PIWI domain and microRNA duplex structure regulate small RNA sorting in Arabidopsis. Nature Communications, 5, 5468. doi:10.1038/ncomms6468