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Plant Cell Physiol

Title:		Jasmonate-induced nicotine formation in tobacco is mediated by tobacco COI1 and JAZ genes
Author(s):		Shoji T; Ogawa T; Hashimoto T;
Address:		"Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192 Japan"
Journal Title:		Plant Cell Physiol
Year:		2008
Volume:		20080519
Issue:		7
Page Number:		1003 - 1012
DOI:		10.1093/pcp/pcn077
ISSN/ISBN:		1471-9053 (Electronic) 0032-0781 (Linking)
Abstract:		"Biosynthesis of many plant alkaloids is enhanced by endogenous accumulation and exogenous application of jasmonates, but the general and specific signaling components are not well understood. In Arabidopsis, jasmonate-induced ZIM-domain-containing (JAZ) proteins have recently been found to be critical transcriptional repressors linking CORONATINE INSENSTIVE1 (COI1)-mediated jasmonate perception and jasmonate-regulated transcriptional regulation. Insect herbivory on tobacco leaves activates the jasmonate signaling pathway, leading to up-regulation of nicotine biosynthesis genes in roots. We show here that roots of COI1-silenced tobacco plants are insensitive to growth inhibition by methyl jasmonate, and do not activate nicotine biosynthesis genes after jasmonate treatment or wounding of leaves. Tobacco JAZ proteins appeared to be rapidly degraded after jasmonate treatment, whereas a C-terminally truncated form lacking the conserved Jas motif did not. When the non-degradable JAZ forms were expressed in tobacco hairy roots, jasmonate induction of nicotine biosynthesis was strongly inhibited. Formation of tobacco alkaloids in jasmonate-elicited tobacco BY-2 cells was also effectively suppressed by the COI1 RNAi (RNA interference) construct and by the dominant-negative truncated JAZ constructs. In addition, jasmonate-mediated induction of nicotine biosynthesis genes was diminished by treatment with a proteasome inhibitor MG132. These results indicate that jasmonate-triggered, COI1-mediated degradation of JAZ repressors activates transcriptional regulation of nicotine biosynthesis genes in tobacco roots"
Keywords:		"Acetates/pharmacology Cyclopentanes/*pharmacology Gene Expression Regulation, Plant/drug effects Genes, Dominant *Genes, Plant Leupeptins/pharmacology Molecular Sequence Data Nicotine/*biosynthesis Oxylipins/*pharmacology Plant Proteins/genetics/*metaboli;"
Notes:		"MedlineShoji, Tsubasa Ogawa, Takayuki Hashimoto, Takashi eng Japan 2008/05/22 Plant Cell Physiol. 2008 Jul; 49(7):1003-12. doi: 10.1093/pcp/pcn077. Epub 2008 May 19"