Poster: Signaling, long distance

Abs # 462: The anti-auxin (p-chlorophenoxyisobutyric acid) resistant mutant aar1 reveals a 2,4-Dichlorophenoxyacetic acid specific pathway in Arabidopsis

Presenter:	Rahman, Abidur , abidur@bio.umass.edu
Authors	Rahman, Abidur  (A) (B)  Ooura, Chiharu  (E)   Baskin, Tobias I (A)   Tsurumi, Seiji  (C)   Tanaka, Atsushi  (B)   Uchimiya, Hirofumi  (D)   Oono, Yutaka  (B) (E)
Affiliations:	(A): Biology Department, University of Massachusetts, Amherst (B): Plant Resource Research Group, Japan Atomic Energy Research Institute (C): RI Center, Kobe University (D): Institute of Molecular and Cellular Biosciences, The University of Tokyo (E): Advanced Science Research Center, Japan Atomic Energy Research Institute
Web Site:	http://www.bio.umass.edu/biology/baskin/abidur/index.htm

We have isolated an anti-auxin (p-chlorophenoxyisobutyric acid, PCIB) resistant Arabidopsis mutant, aar1, that shows specific resistance to physiological and molecular responses regulated by 2,4-dichlorophenoxy acetic acid (2,4-D). Compared to wild type, aar1 has longer hypocotyls both in light and darkness and produces more lateral roots. The mutant aar1 is resistant to 2,4-D-induced growth responses, including inhibition of root growth, stimulation of hypocotyl length, and induction of lateral roots, yet nevertheless shows a wild-type response in the same assays to indole-3-acetic acid (IAA) and 1-naptheleneacetic acid (NAA). GUS expression analysis in aar1DR5::GUS and real time PCR quantification of IAA11 expression confirmed that aar1 mutation specifically alters 2,4-D signaling in Arabidopsis. Taken together these results suggest that PCIB response pathway in Arabidopsis is closely associated with 2,4-D pathway and 2,4-D/IAA pathway in planta is at least in part different.