Hypomethylated drm1 drm2 cmt3 mutant phenotype of Arabidopsis thaliana is related to auxin pathway impairment (original) (raw)

Physiological characteristics of two auxin-resistant mutants of Arabidopsis thaliana, aux-2 and Dwf

Plant Growth Regulation, 1987

Two auxin-resistant mutants of Arabidopsis thaliana L. have been characterized physiologically: aux-2 is a recessive mutation and is unlinked to a dominant mutation, Dwf, which is apparently lethal when homozygous. The progeny of selfed Dwfplants segregate into Dwf (agravitropic) and dwf + (normal) phenotypes. aux-2 phenotype was indistinguishable from the wild-type on criteria other than resistance to exogenous auxins: 3-fold to 2,4-D and 2-fold to IAA. On the other hand, Dwf plants had a typical dwarf phenotype with single unbranched roots which lacked hairs. Compared to the wild-type, Dwfseedling roots were highly resistant to exogenous auxins: 2000-fold to 2,4-D and 360-fold to IAA. Both aux-2 and Dwf were normal in their response to exogenous ABA. The dwarf phenotype was insensitive to gibberellins but root hair formation was restored by application of auxins. The results indicate that altered auxin phsysiology can lead to agravitropism and dwarfism.