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Author Arimura, Gen ichiro ♦ Garms, Stefan ♦ Maffei, Massimo ♦ Bossi, Simone ♦ Schulze, Birgit ♦ Leitner, Margit ♦ Mithöfer, Axel ♦ Boland, Wilhelm
Source SpringerLink
Content type Text
Publisher Springer-Verlag
File Format PDF
Copyright Year ©2007
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Life sciences; biology
Subject Keyword Calcium ♦ Ethylene ♦ Jasmonic acid ♦ Medicago truncatula ♦ Terpenoid ♦ Forestry ♦ Ecology ♦ Agriculture ♦ Plant Sciences
Abstract Plant volatiles emitted by Medicago truncatula in response to feeding larvae of Spodoptera exigua are composed of a complex blend of terpenoids. The cDNAs of three terpene synthases (TPSs), which contribute to the blend of terpenoids, were cloned from M. truncatula. Their functional characterization proved MtTPS1 to be a β-caryophyllene synthase and MtTPS5 to be a multi-product sesquiterpene synthase. MtTPS3 encodes a bifunctional enzyme producing (E)-nerolidol and geranyllinalool (precursors of C11 and C16 homoterpenes) from different prenyl diphosphates serving as substrates. The addition of jasmonic acid (JA) induced expression of the TPS genes, but terpenoid emission was higher from plants treated with JA and the ethylene precursor 1-amino-cyclopropyl-1-carboxylic acid. Compared to infested wild-type M. truncatula plants, lower amounts of various sesquiterpenes and a C11–homoterpene were released from an ethylene-insensitive mutant skl. This difference coincided with lower transcript levels of MtTPS5 and of 1-deoxy-d-xylulose-5-phosphate synthase (MtDXS2) in the damaged skl leaves. Moreover, ethephon, an ethylene-releasing compound, modified the extent and mode of the herbivore-stimulated Ca2+ variations in the cytoplasm that is necessary for both JA and terpene biosynthesis. Thus, ethylene contributes to the herbivory-induced terpenoid biosynthesis at least twice: by modulating both early signaling events such as cytoplasmic Ca2+-influx and the downstream JA-dependent biosynthesis of terpenoids.
ISSN 00320935
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2007-10-09
Publisher Place Berlin/Heidelberg
e-ISSN 14322048
Journal Planta
Volume Number 227
Issue Number 2
Page Count 12
Starting Page 453
Ending Page 464


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Source: SpringerLink