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New Phytol

Title:		RuBPCase activase (RCA) mediates growth-defense trade-offs: silencing RCA redirects jasmonic acid (JA) flux from JA-isoleucine to methyl jasmonate (MeJA) to attenuate induced defense responses in Nicotiana attenuata
Author(s):		Mitra S; Baldwin IT;
Address:		"Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knoll-Strasse 8, 07745, Jena, Germany"
Journal Title:		New Phytol
Year:		2014
Volume:		20131111
Issue:		4
Page Number:		1385 - 1395
DOI:		10.1111/nph.12591
ISSN/ISBN:		1469-8137 (Electronic) 0028-646X (Print) 0028-646X (Linking)
Abstract:		"* RuBPCase activase (RCA), an abundant photosynthetic protein, is strongly down-regulated in response to Manduca sexta's oral secretion (OS) in Nicotiana attenuata. RCA-silenced plants are impaired not only in photosynthetic capacity and growth, but also in jasmonic acid-isoleucine (JA-Ile) signaling, and herbivore resistance mediated by JA-Ile-dependent defense traits. These responses are consistent with a resource-based growth-defense trade-off. * As JA + Ile supplementation of OS restored wild-type (WT) levels of JA-Ile, defenses and resistance to M. sexta, but OS supplemented individually with JA or Ile did not, the JA-Ile deficiency of RCA-silenced plants could not be attributed to lower JA or Ile pools or JAR4/6 conjugating activity. Similar levels of JA-Ile derivatives after OS elicitation indicated unaltered JA-Ile turnover, and lower levels of other JA conjugates ruled out competition from other conjugation reactions. * RCA-silenced plants accumulated more methyl jasmonate (MeJA) after OS elicitation, which corresponded to increased jasmonate methyltransferase (JMT) activity. RCA silencing phenocopies JMT overexpression, wherein elevated JMT activity redirects OS-elicited JA flux towards inactive MeJA, creating a JA sink which depletes JA-Ile and its associated defense responses. * Hence, RCA plays an additional non-photosynthetic role in attenuating JA-mediated defenses and their associated costs, potentially allowing plants to anticipate resource-based constraints on growth before they actually occur"
Keywords:		Acetates/*metabolism Animals Cyclopentanes/*metabolism/pharmacology *Gene Silencing/drug effects Herbivory/drug effects Isoleucine/*metabolism Manduca/drug effects/physiology Methylation Methyltransferases/metabolism Oxylipins/*metabolism/pharmacology Pla;
Notes:		"MedlineMitra, Sirsha Baldwin, Ian T eng 293926/ERC_/European Research Council/International Research Support, Non-U.S. Gov't England 2014/02/05 New Phytol. 2014 Mar; 201(4):1385-1395. doi: 10.1111/nph.12591. Epub 2013 Nov 11"