Morteza Barati - Department of Agronomy & Plant Breeding, University of Zanjan
Mohamad Reza Azimi - Department of Agronomy & Plant Breeding, University of Zanjan
Mohamad Reza Naghavi - Agricultral & Natural Resourses Collage, University of Tehran
Ehsan Mohseni Fard - Agricultral & Natural Resourses Collage, University of Tehran

MicroRNAs (miRNAs) are small regulatory RNAs consisting of about 18–22 nucleotides which regulate gene expression at the posttranscriptional levels [1]. In plants, miRNAs are involved in controlling differentiation and development, signaling transduction and response to biotic and abiotic stress [2]. A comparative genomics study has shown that many miRNAs are highly evolutionarily conserved from species to species in the plant kingdom. This feature gives a powerful approach to their identification using comparative genomics. Mature miRNA is generated through two-step cleavage of primary miRNA (pri-miRNA) and precursor miRNA (pre-miRNA). When two mature microRNAs originate from opposite arms of the same premiRNA, they are denoted with a -3p or -5p suffix.