Arabidopsis seedling growth response and recovery to ethylene. A kinetic analysis.
Responses to the plant hormone ethylene are mediated by a family of five receptors in Arabidopsis that act in the absence of ethylene as negative regulators of response pathways. In this study, we examined the rapid kinetics of growth inhibition by ethylene and growth recovery after ethylene withdrawal in hypocotyls of etiolated seedlings of wild-type and ethylene receptor-deficient Arabidopsis lines. This analysis revealed that there are two phases to growth inhibition by ethylene in wild type: a rapid phase followed by a prolonged, slower phase. Full recovery of growth occurs approximately 90 min after ethylene removal. None of the receptor null mutations tested had a measurable effect on the two phases of growth inhibition. However, loss-of-function mutations in ETR1, ETR2, and EIN4 significantly prolonged the time for recovery of growth rate after ethylene was removed. Plants with an etr1-6;etr2-3;ein4-4 triple loss-of-function mutation took longer to recover than any of the single mutants, while the ers1;ers2 double mutant had no effect on recovery rate, suggesting that receiver domains play a role in recovery. Transformation of the ers1-2;etr1-7 double mutant with wild-type genomic ETR1 rescued the slow recovery phenotype, while a His kinase-inactivated ETR1 construct did not. To account for the rapid recovery from growth inhibition, a model in which clustered receptors act cooperatively is proposed.
Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA.
Brad M
BM
Binder
Ronan C
RC
O'malley
Wuyi
W
Wang
Jeannette M
JM
Moore
Brian M
BM
Parks
Edgar P
EP
Spalding
Anthony B
AB
Bleecker
D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D000071677:Histidine Kinase; D018546:Hypocotyl / Q000254:growth & development; D009154:Mutation; D010937:Plant Growth Regulators / Q000494:pharmacology / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000502:physiology; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors
D029681:Arabidopsis Proteins; D005030:Ethylenes; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C083750:ethylene receptors, plant; C036216:ethylene; D011494:Protein Kinases; D000071677:Histidine Kinase