title: Manipulation of Arabidopsis fatty acid amide hydrolase expression modifies plant growth and sensitivity to N-acylethanolamines.
abstract: In vertebrates, the endocannabinoid signaling pathway is an important lipid regulatory pathway that modulates a variety of physiological and behavioral processes. N-Acylethanolamines (NAEs) comprise a group of fatty acid derivatives that function within this pathway, and their signaling activity is terminated by an enzyme called fatty acid amide hydrolase (FAAH), which hydrolyzes NAEs to ethanolamine and their corresponding free fatty acids. Bioinformatic approaches led to the identification of plant homologues of FAAH that are capable of hydrolyzing NAEs in vitro. To better understand the role of NAEs in plants, we identified T-DNA knockouts to Arabidopsis FAAH (AtFAAH; At5g64440) and generated plants overexpressing AtFAAH. Here we show that seeds of AtFAAH knockouts had elevated levels of endogenous NAEs, and seedling growth was hypersensitive to exogenously applied NAE. On the other hand, seeds and seedlings of AtFAAH overexpressors had lower endogenous NAE content, and seedlings were less sensitive to exogenous NAE. Moreover, AtFAAH overexpressors displayed enhanced seedling growth and increased cell size. AtFAAH expression and FAAH catalytic activity increased during seed germination and seedling growth, consistent with the timing of NAE depletion during seedling establishment. Collectively, our results show that AtFAAH is one, but not the only, modulator of endogenous NAE levels in plants, and that NAE depletion likely participates in the regulation of plant growth.
authors.affiliation: Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA.
authors.forename: Yuh-Shuh
authors.initials: YS
authors.lastname: Wang
authors.forename: Rhidaya
authors.initials: R
authors.lastname: Shrestha
authors.forename: Aruna
authors.initials: A
authors.lastname: Kilaru
authors.forename: William
authors.initials: W
authors.lastname: Wiant
authors.forename: Barney J
authors.initials: BJ
authors.lastname: Venables
authors.forename: Kent D
authors.initials: KD
authors.lastname: Chapman
authors.forename: Elison B
authors.initials: EB
authors.lastname: Blancaflor
mesh_terms: D000581:Amidohydrolases / Q000096:biosynthesis* / Q000737:chemistry*; D017360:Arabidopsis / Q000201:enzymology*; D063385:Cannabinoid Receptor Modulators / Q000378:metabolism; D002384:Catalysis; D004983:Ethanolamines / Q000494:pharmacology*; D018506:Gene Expression Regulation, Plant; D006868:Hydrolysis; D008055:Lipids / Q000737:chemistry; D008861:Microsomes / Q000378:metabolism; D018521:Plant Physiological Phenomena; D030821:Plants, Genetically Modified; D012639:Seeds; D015398:Signal Transduction; D013997:Time Factors; D000099252:Fatty Acid Amide Hydrolases
chemical_list: D000581:Amidohydrolases; D063385:Cannabinoid Receptor Modulators; D004983:Ethanolamines; D008055:Lipids; D000099252:Fatty Acid Amide Hydrolases; C022203:N-acylethanolamines