Abstract: MicroRNAs (miRNAs) are - 21 nucleotide (nt) , endogenous and encoding RNAs that play important regulatory roles in growth and development by targetingmRNAs for direct cleavage or translational repression in plants . To analyze the biological function of miR396, we placed two synthetic precursors, MIR396a or MIR396b , under the control of the enhanced
Cauliflower mosaic virus (CaMV) 35S promoter in a plant transformation vector ( pOCA30) and transformed the constructs into Arabidopsis . Genetic analysis showed that flower stigmas of 35S: MIR396 transgenic Arabidopsis were curve and siliques of miR396 transgenic plants were abnormal. In addition , Northern blot analysis showed that the miR396 miRNAs and levels of MIR396 precursor transcripts were significantly increased in transgenic miR396 plants compared with control. These results strongly supported that miR396 played an important role in plant flower development .

Key words: Arabidopsis thaliana