ABA and Ethylene
Blancaflor, Elison B , Teaster, Neal , Tang, Yuhong , Motes, Christy M , Wang, Yuh-Shuh , Wiant, William C , Cotter, Matthew Q , Kilaru, Aruna , Venables, Barney J , Hasenstein, Karl , Gonzalez, Gabriel , Chapman, Kent D .
N-acylethanolamine (NAE) metabolism impacts growth and interacts with ABA signaling in Arabidopsis thaliana seedlings.
In mammalian systems the metabolism of the N-acylethanolamine (NAE) group of lipids is part of the endocannabinoid signaling system where NAEs activate G-protein-coupled cannabinoid receptors, which in turn regulate an array of physiological and behavioral processes. Although, the occurrence and metabolism of NAEs is conserved among eukaryotes, the physiological functions of these lipids have been investigated mostly in animals. In mammals, the NAE hydrolyzing enzyme, fatty acid amide hydrolase (FAAH) terminates NAE signaling. Recently, we described an Arabidopsis FAAH, which when over-expressed or down-regulated in Arabidopsis seedlings, confers tolerance or hypersensitivity to the growth inhibitory effects of exogenous NAEs. NAEs, which are most abundant in seeds are depleted during imbibition concomitant with FAAH expression suggesting that the catabolism of NAEs is necessary for cell expansion that accompanies germination and seedling establishment. Transcript profiling of NAE-treated seedlings revealed that a number of genes regulated by NAE where also ABA responsive. Exogenous ABA and NAE together produced a more severe effect on seedling growth than either compound alone, suggesting a synergistic interaction between NAE and ABA. ABA insensitive (abi) mutants were insensitive to NAE and to the synergistic effects of NAE and ABA. AtFAAH over-expressing seedlings, although tolerant to high NAE, were hypersensitive to ABA. Our data indicate that NAE metabolism acts in concert with ABA to negatively regulate seedling development in Arabidopsis. Our results provide evidence that NAE metabolism, which has been implicated mostly in the regulation of animal physiology, impacts a major hormone signaling pathway in plants (Supported by DOE grant DE-FG02-05ER15647).
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1 - Samuel Roberts Noble Foundation, Plant Biology Division, 2510 Sam Noble Parkway, Ardmore, Oklahoma, 73401, USA
2 - University of North Texas, Department of Biological Sciences
3 - Samuel Roberts Noble Foundation, Plant Biology Division
4 - University of Louisiana, Department of Biology
Presentation Type: ASPB Minisymposium
Location: Continental B/Hilton
Date: Wednesday, July 11th, 2007
Time: 8:30 AM