Abstract
The microRNAs, miR165/166, target a ClassIII homeodomain-leucine zipper (HD-ZIPIII) family whose members are essential transcription factors for plant normal growth and development. The fine tuning of spatial and temporal regulation of HD-ZIPIII expression by miR165/166 controls stem cell maintenance, vascular differentiation, leaf patterning and so on. An activation tagging line D10 has many phenotypes such as dwarf, disruption of inflorescence and phyllotaxy, and fasciation of inflorescence stems. Furthermore, the D10 line presents a semi sterile phenotype because of abnormal development of flower organs. We identified the T-DNA insertion site of the D10 line, and found that the T-DNA with 35S enhancers was inserted between the MIR166c and MIR166d genes. RT-PCR and RNA gel blot analysis revealed that the expression levels of the two precursors and miR166 in the 7-d-seedlings of the D10 line were elevated significantly than the wild type (WT) plant. Expression patterns of five HD-ZIPIII genes in the D10 line were different from WT. The results suggest that overexpression of MIR166c and/or MIR166d genes in the D10 line causes the alteration of HD-ZIPIII expressions.
