Elucidation of auxin signaling mechanism through identification of antiauxin resistant gene

点击翻译按钮获取中文摘要

An antiauxin resistant1 (aar1) mutant has been identified in a screen for resistance to the antiauxin, p-chlorophenoxy-isobutyric acid (PCIB) The aar1 was also resistant to synthetic auxin 2,4-D. To understand molecular mechanism of auxin action, genetic analyses of aar1 mutant were carried out. The aarl-1 allele harbors multi-gene deletions in T6G15 region on chromosome 4. 2,4-D responsiveness was restored by transformation with one of the genes missing and the 2,4-D-resistant phenotype was reproduced by decreasing the expression of the same gene in wild type with a RNAi construct. The gene encodes a small, acidic protein (SMAP1) with unknown function and present in plants, animals, and invertebrates but not in fungi or prokaryotes. GFP fusion analysis of SMAP1 suggested that SMAP1 is localized in nucleus and its C-terminal region is functionally important. Taken together, the results implied the presence of a novel auxin-signaling pathway through conserved protein SMAP1.