Abstract
miR156/157 regulates developmental phase transition by controlling the expression of SBP-box genes, and overexpression of miR156/157 in Arabidopsis caused the retardation of phase transition and the loss of apical dominance. miR156/157 and SBP-box genes are evolutionally conserved across all major lineages of plants. To elucidate the conservation of miR156/157 function between different species, we compared transgenic Arabidopsis and torenias (Torenia fournieri) overexpressing Arabidopsis miR157b. miR157b overexpressing (miR157b-ox) torenia produced many juvenile leaves and reduced apical dominance as well as miR157b-ox Arabidopsis. The fresh weight and the number of leaves per plant increased in miR157b-ox torenias, suggesting that miR157b-ox was useful for increasing of biomass. Expressions of 3 of 6 isolated torenia SBP-box genes were reduced in miR157b-ox torenias. This reduction seemed to be derived from the difference of the target sequence. These results indicate that miR156/157 precisely control the expression of the SBP-box genes by the difference of its expression pattern and the target sequence.
