Cloning And Priliminary Function Analysis Of Rice MiR156

miRNAs, a type of small non-coding RNAs (about 21nt in size), can regulate gene expression by mediating mRNA degradation or translational inhibition. MiR156 family is ancient and conserved in plant. The family has 12 members (miR156a-1), respectively distributed in chromosome 1,2,4,5,6,8 and 9 in rice plants. To discover the roles of miR156 in the growth and development of rice plants and the pathogenesis of rice viruses, the miR156 genes were firstly cloned from rice plants and then ligated into plasmid pCAMBIA1300 so that vectors containing Os-miR156 genes were constructed under the control of ubiquitin promoter. Meanwhile, Os-IPS1 gene was cloned from rice plants and used as a backbone for synthetizing target mimicry by over-lapping PCR. Then the target mimicry also was ligated into plasmid pCAMBIA1300 for inhibiting Os-miR156 activity. These constructed vectors were respectively transformed into rice calli by agrobacterium-mediated method and transgenic seedlings were transplanted in greenhouse. Molecular experiments revealed the Os-miR156 gene have been stably integrated into chromosome and expressed at high level in transgenic rice plants. Compared with the non-transgenic plants, the transgenic plants (TO) displayed abnormal phenotypes, including pronounced dwarf, increased tillering, delaying flowering, few seeds or even no seed. Compared with control seeds, the transgenic seeds displayed compact size, their inner-glumes with long awn but no hair, slow germination and growth. We also found that the growth and development of transgenic rice plants are slower than these nontransgenic plants by observing semi-thin sections. qRT-PCR results showed that the expressions of SPL genes and some miRNAs have been differently affected in transgenic plants, in which the expressions of SPL11,SPL13,SPL18,miR164 and miR172 are remarkable down-regulated. These results provided a foundation for further studying the roles of Os-miR156 in the growth and development of rice plants and pathogenesis of rice viruses.