Characterization of a Multiple Branching Mutant of Arabidopsis Isolated by Activation Tagging Mutagenesis

Abstract

The ATL98246 mutant plant that showed a multiple branching phenotype was isolated from activation tagging lines of Arabidopsis Columbia ecotype (Col-0). The ATL98246 mutant plant exhibited reduced apical dominance and bushy dwarf phenotypes in the long day condition. The expression of the At5g19700 gene was increased by the CaMV 35S enhancer in the ATL98246 mutant plant. Recapitulation analysis by ectopic expression of the At5g19700 gene under the CaMV 35S promoter identified that the At5g19700 gene was responsible for the multiple branching phenotype of the ATL98246 mutant plant. The At5g19700 gene encodes a member of the MATE transporter protein family. The At5g19700::GFP fusion protein was located in the vacuolar membrane. RT-PCR analysis with different tissues of the wild type plants suggested that the At5g19700 gene was expressed in the leaves, roots, stems, floral clusters, and siliques. The expression levels of some IAA (Indole-3-Acetic Acid) inducible genes in different tissues, for example IAA5, IAA6 and IAA19 genes, were changed in the ATL98246 mutant plant, which may suggest that auxin be involved in the multiple branching phenotype in the ATL98246 mutant plant.