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Plant Signal Behav

Title:		Formation and exudation of non-volatile products of the arabidiol triterpenoid degradation pathway in Arabidopsis roots
Author(s):		Sohrabi R; Ali T; Harinantenaina Rakotondraibe L; Tholl D;
Address:		"a Department of Biological Sciences , Virginia Tech , Blacksburg , VA , USA. b Division of Medicinal Chemistry and Pharmacognosy, Ohio State University , Columbus , OH , USA"
Journal Title:		Plant Signal Behav
Year:		2017
Volume:		12
Issue:		1
Page Number:		e1265722 -
DOI:		10.1080/15592324.2016.1265722
ISSN/ISBN:		1559-2324 (Electronic) 1559-2316 (Print) 1559-2316 (Linking)
Abstract:		"Triterpenoids produced by plants play important roles in the protection against biotic stress. Roots of Arabidopsis thaliana produce different triterpenoids, which include the tricyclic triterpene diol, arabidiol. In a degradation reaction induced by infection with the oomycete pathogen, Pythium irregulare, arabidiol is cleaved to the 11-carbon volatile homoterpene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and the 19-carbon ketone, apo-arabidiol. The arabidiol pathway and its volatile breakdown product DMNT have been implicated in the defense against P. irregulare infection. Here we show that the non-volatile breakdown product apo-arabidiol is further converted to the acetylated derivative alpha-14-acetyl-apo-arabidiol via a presumed epimerization and subsequent acetylation reaction. alpha-14-acetyl-apo-arabidiol and the detected intermediates in the derivatization pathway are partially exuded from the root indicating possible defensive activities of these molecules in the rhizosphere. The conversion steps of apo-arabidiol vary among different Arabidopsis accessions and are present in only rudimentary form in the close relative Arabidopsis lyrata, which supports an intra- and inter-specific modularity in triterpenoid metabolism"
Keywords:		"Alkenes/metabolism Arabidopsis/*metabolism Arabidopsis Proteins/metabolism Gene Expression Regulation, Plant Plant Roots/*metabolism Triterpenes/*metabolism Volatile Organic Compounds/metabolism Accession variation Arabidopsis defense homoterpene root tri;"
Notes:		"MedlineSohrabi, Reza Ali, Tehane Harinantenaina Rakotondraibe, Liva Tholl, Dorothea eng 2016/12/06 Plant Signal Behav. 2017 Jan 2; 12(1):e1265722. doi: 10.1080/15592324.2016.1265722"