Premium
Evidence for altered polar and lateral auxin transport in the gravity persistent signal ( gps ) mutants of Arabidopsis
Author(s) -
NADELLA VIJAYANAND,
SHIPP MATTHEW J.,
MUDAY GLORIA K.,
WYATT SARAH E.
Publication year - 2006
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2005.01451.x
Subject(s) - auxin , inflorescence , mutant , arabidopsis , polar auxin transport , biology , gravitropism , wild type , arabidopsis thaliana , microbiology and biotechnology , botany , gene , genetics
Plant shoots do not respond when they are reoriented relative to gravity at 4 °C. However, when returned to vertical at room temperature, these organs bend in response to the previous cold gravistimulation. The inflorescence stem of the Arabidopsis thaliana gravity persistent signal (gps) mutants respond abnormally after the cold gravistimulation: gps 1 does not bend when returned to room temperature, gps 2 bends the wrong way and gps 3 over‐responds, curving past the predicted angle. In wild type and the mutants, basipetal auxin transport in the inflorescence stem was abolished at 4 °C but restored when plants were returned to room temperature. In gps 1, auxin transport was increased; in both gps 2 and gps 3, no significant difference was found when compared to wild type. Expression of the auxin‐inducible P IAA2 ::GUS reporter gene, indicated that auxin‐induced gene expression was redistributed to the lower side of the inflorescence stem in wild type after gravistimulation at 4 °C. In gps 1, no asymmetries in P IAA2 ::GUS expression were seen. In gps 2, P IAA2 ::GUS expression was localized to the upper side of the stem and in gps 3, asymmetric P IAA2 ::GUS expression was extended throughout the elongation zone of the inflorescence stem. These results are consistent with altered lateral Indole‐3‐acetic‐acid (IAA) gradients being responsible for the phenotype of each mutant.