Abstract
Leaf development is regulated by several factors, and each factor should function correctly in adaxial- or abaxial-side of leaf primordia. Previously we reported that the expression domain of a HD-Zip III gene, PHB, is restricted in the non FIL-expressed cells by the miR165/166-mediated gene repression. We also revealed that six MIR165/166 genes are expressed only in the abaxial side, resulting in the side-specific repression of PHB expression. Here, the promoter-reporter analyses show that MIR165A and MIR166A are expressed in the abaxial-epidermal cells, and that the expression of MIR165B and MIR166B are observed in the cells locating in the abaxial-side. Then, we crossed the transgenic plant hovering mutated pri-miR165a driven by MIR165A promoter with the transgenic line having the GFP fused with mutated miR165/166-recognition sequence driven by CaMV 35S promoter. The F1 plants show that the GFP expression is observed only in the adaxial-side of leaf primordia, and the GFP-expression domain is almost same as that of HD-Zip III. These results suggest that MIR165A could repress the expression of HD-Zip III in non-cell-autonomous manner.
