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BMC Plant Biol

Title:		Fatty acid-amino acid conjugates are essential for systemic activation of salicylic acid-induced protein kinase and accumulation of jasmonic acid in Nicotiana attenuata
Author(s):		Hettenhausen C; Heinrich M; Baldwin IT; Wu J;
Address:
Journal Title:		BMC Plant Biol
Year:		2014
Volume:		20141128
Issue:
Page Number:		326 -
DOI:		10.1186/s12870-014-0326-z
ISSN/ISBN:		1471-2229 (Electronic) 1471-2229 (Linking)
Abstract:		"BACKGROUND: Herbivory induces the activation of mitogen-activated protein kinases (MAPKs), the accumulation of jasmonates and defensive metabolites in damaged leaves and in distal undamaged leaves. Previous studies mainly focused on individual responses and a limited number of systemic leaves, and more research is needed for a better understanding of how different plant parts respond to herbivory. In the wild tobacco Nicotiana attenuata, FACs (fatty acid-amino acid conjugates) in Manduca sexta oral secretions (OS) are the major elicitors that induce herbivory-specific signaling but their role in systemic signaling is largely unknown. RESULTS: Here, we show that simulated herbivory (adding M. sexta OS to fresh wounds) dramatically increased SIPK (salicylic acid-induced protein kinase) activity and jasmonic acid (JA) levels in damaged leaves and in certain (but not all) undamaged systemic leaves, whereas wounding alone had no detectable systemic effects; importantly, FACs and wounding are both required for activating these systemic responses. In contrast to the activation of SIPK and elevation of JA in specific systemic leaves, increases in the activity of an important anti-herbivore defense, trypsin proteinase inhibitor (TPI), were observed in all systemic leaves after simulated herbivory, suggesting that systemic TPI induction does not require SIPK activation and JA increases. Leaf ablation experiments demonstrated that within 10 minutes after simulated herbivory, a signal (or signals) was produced and transported out of the treated leaves, and subsequently activated systemic responses. CONCLUSIONS: Our results reveal that N. attenuata specifically recognizes herbivore-derived FACs in damaged leaves and rapidly send out a long-distance signal to phylotactically connected leaves to activate MAPK and JA signaling, and we propose that FACs that penetrated into wounds rapidly induce the production of another long-distance signal(s) which travels to all systemic leaves and activates TPI defense"
Keywords:		Cyclopentanes/*metabolism Fatty Acids/metabolism Herbivory Isoleucine/metabolism Mitogen-Activated Protein Kinases/genetics/*metabolism Oxylipins/*metabolism Plant Leaves/enzymology Plant Proteins/genetics/metabolism Protease Inhibitors/metabolism Salicyl;
Notes:		"MedlineHettenhausen, Christian Heinrich, Maria Baldwin, Ian T Wu, Jianqiang eng Research Support, Non-U.S. Gov't England 2014/11/29 BMC Plant Biol. 2014 Nov 28; 14:326. doi: 10.1186/s12870-014-0326-z"