Auxin and ethylene promote root hair elongation in Arabidopsis.
Genetic and physiological studies implicate the phytohormones auxin and ethylene in root hair development. To learn more about the role of these compounds, we have examined the root hair phenotype of a number of auxin- and ethylene-related mutants. In a previous study, Masucci and Schiefelbein (1996) showed that neither the auxin response mutations aux1 and axr1 nor the ethylene response mutations etr1 and ein2 have a significant effect on root hair initiation. In this study, we found that mutants deficient in either auxin or ethylene response have a pronounced effect on root hair length. Treatment of wild-type, axr1 and etr1 seedlings with the synthetic auxin, 2,4-D, or the ethylene precursor ACC, led to the development of longer root hairs than untreated seedlings. Furthermore, axr1 seedlings grown in the presence of ACC produce ectopic root hairs and an unusual pattern of long root hairs followed by regions that completely lack root hairs. These studies indicate that both auxin and ethylene are required for normal root hair elongation.
Department of Biology, Indiana University, Bloomington 47405, USA.
R J
RJ
Pitts
A
A
Cernac
M
M
Estelle
D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D000596:Amino Acids / Q000494:pharmacology; D000598:Amino Acids, Cyclic; D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology*; D017343:Genes, Plant; D006133:Growth Substances; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics
C100794:AUX1 protein, Arabidopsis; C081977:AXR1 protein, Arabidopsis; D000596:Amino Acids; D000598:Amino Acids, Cyclic; D029681:Arabidopsis Proteins; D005030:Ethylenes; D006133:Growth Substances; D007210:Indoleacetic Acids; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; D015084:2,4-Dichlorophenoxyacetic Acid; C023863:1-aminocyclopropane-1-carboxylic acid; C036216:ethylene