| Abstract Detail
Hormone Biology Negi, Sangeeta [1], Williams, Benjamin [2], Ivanchenko, Maria [3], Muday, Gloria K [4]. Ethylene negatively regulates lateral root development in Arabidopsis thaliana. Molecular genetic approaches have recently provided insight into the molecular and physiological basis of root development. Experimental evidence has clearly shown a role for auxin signaling and transport in lateral root initiation and elongation. Interplay between auxin and ethylene has been shown for root elongation, while a role of ethylene in root development is not yet clear. In this study we have used ethylene signaling and synthesis mutants to study the role of ethylene in lateral root development. An ethylene overproducing mutant, eto1-1, produces very few lateral roots when compared to wild type seedlings. Arabidopsis wild type Columbia seedlings show a dose dependent decrease in lateral root numbers when grown on the ethylene precursor, ACC (1-aminocyclopropane-1-carboxylic acid). Additionally, two mutants with defects in ethylene signaling, ein2-5 and etr1-3, show increased lateral root numbers and are insensitive to the inhibitory effect of ACC on lateral root numbers. These results are consistent with ethylene negatively regulating the lateral root development. We are also investigating whether ethylene prevents lateral root formation by cross talk with auxin. Exogenous auxin enhances lateral root formation in wild-type, etr1-3, and ein2-5, with similar dose response curves, except at very high auxin doses, which reduce lateral root numbers in wild-type, but not the ethylene signaling mutants. Experiments are underway to identify the mechanism for the ethylene-auxin cross talk and to ask if flavonoids, which may act as endogenous auxin transport inhibitors, coordinate this hormonally regulated lateral root formation.
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1 - Wake Forest University, Biology, Winston-Salem, NC, 27106, USA
2 - Wake Forest University, Deparment of Biology
3 - Oregon State University, Botany
4 - Wake Forest University, Biology
Keywords:
auxin
ethylene
lateral root.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P35041
Abstract ID:1955 |
