02572nas a2200205   4500008004100000022001400041245014700055210006900202260008000271300001200351490000800363520174800371100002502119700002302144700002002167700001802187700002102205700001602226856012402242       2012                        eng d  a0032-088900aMYB8 Controls inducible phenolamide levels by activating three novel hydroxycinnamoyl-coenzyme a:polyamine transferases in nicotiana attenuata0 aMYB8 Controls inducible phenolamide levels by activating three n  a15501 MONONA DRIVE, ROCKVILLE, MD 20855 USAbAMER SOC PLANT BIOLOGISTScJAN  a389-4070 v1583 a<p>A large number of plants accumulate N-acylated polyamines (phenolamides [PAs]) in response to biotic and/or abiotic stress conditions. In the native tobacco (Nicotiana attenuata), the accumulation of two major PAs, caffeoylputrescine and dicaffeoylspermidine (DCS), after herbivore attack is known to be controlled by a key transcription factor, MYB8. Using a broadly targeted metabolomics approach, we show that a much larger spectrum of PAs composed of hydroxycinnamic acids and two polyamines, putrescine and spermidine, is regulated by this transcription factor. We cloned several novel MYB8-regulated genes, annotated as putative acyltransferases, and analyzed their function. One of the novel acyltransferases (AT1) is shown to encode a hydroxycinnamoyl-coenzyme A: putrescine acyltransferase responsible for caffeoylputrescine biosynthesis in tobacco. Another gene (acyltransferase DH29), specific for spermidine conjugation, mediates the initial acylation step in DCS formation. Although this enzyme was not able to perform the second acylation toward DCS biosynthesis, another acyltransferase gene, CV86, proposed to act on monoacylated spermidines, was isolated and partially characterized. The activation of MYB8 in response to herbivore attack and associated signals required the activity of LIPOXYGENASE3, a gene involved in jasmonic acid (JA) biosynthesis in N. attenuata. These new results allow us to reconstruct a complete branch in JA signaling that defends N. attenuata plants against herbivores: JA via MYB8's transcriptional control of AT1 and DH29 genes controls the entire branch of PA biosynthesis, which allows N. attenuata to mount a chemically diverse (and likely efficient) defense shield against herbivores.</p>1 aOnkokesung, Nawaporn1 aGaquerel, Emmanuel1 aKotkar, Hemlata1 aKaur, Harleen1 aBaldwin, Ian, T.1 aGalis, Ivan  uhttps://library.ncl.res.in/content/myb8-controls-inducible-phenolamide-levels-activating-three-novel-hydroxycinnamoyl-0