Genetic characterization of mutants resistant to the antiauxin -chlorophenoxyisobutyric acid reveals that , a gene encoding a DCN1-like protein, regulates responses to the synthetic auxin 2,4-dichlorophenoxyacetic acid in Arabidopsis roots

Biswas, K. K.*; Oura, Chiharu*; Higuchi, Kanako*; Miyazaki, Yuji*; Nguyen, V. V.*; Rahman, A.*; Uchimiya, Hirofumi*; Kiyosue, Tomohiro*; Koshiba, Tomokazu*; Tanaka, Atsushi; Narumi, Issei; Ono, Yutaka

We screened mutants for root growth resistance to a putative antiauxin, PCIB, which inhibits auxin action by interfering the upstream auxin signaling events. Eleven PCIB-resistant mutants were obtained. Genetic mapping indicates that the mutations are located in at least 5 independent loci including two known auxin-related loci, and . mutants (s) , and were also resistant to 2,4-D as shown by a root growth assay. Positional cloning of revealed that the gene encodes a protein with a domain of unknown function (DUF298), which has not previously been implicated in auxin signaling. The protein has a putative nuclear localization signal and shares homology with the DCN-1 protein through the DUF298 domain. The results also indicate that PCIB can facilitate the identification of factors involved in auxin or auxin-related signaling.