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J Chem Ecol

Title:		Co-variation of chemical and mechanical defenses in lima bean (Phaseolus lunatus L.)
Author(s):		Ballhorn DJ; Godschalx AL; Kautz S;
Address:		"Department of Biology, Portland State University, Portland, OR 97201, USA. ballhorn@pdx.edu"
Journal Title:		J Chem Ecol
Year:		2013
Volume:		20130217
Issue:		3
Page Number:		413 - 417
DOI:		10.1007/s10886-013-0255-6
ISSN/ISBN:		1573-1561 (Electronic) 0098-0331 (Linking)
Abstract:		"Plants usually express multiple chemical and mechanical defenses simultaneously. The interplay of these defenses is still poorly understood, as predictions range from negative associations such as allocation tradeoffs to positive correlations forming synergistic defense syndromes. Surprisingly, little empirical evidence exists on the co-variation of multiple plant defenses. In the present study, we analyzed different genotypes of lima bean (Phaseolus lunatus L.) for the expression of two direct chemical defenses [cyanogenic potential (constitutive), polyphenol oxidase activity (inducible)], two indirect chemical defenses [volatiles (VOCs) and extrafloral nectar (EFN; both inducible)] and a constitutive mechanical defense (hook-shaped trichomes). While the occurrence of trichomes was positively correlated with cyanogenesis, these traits showed a tradeoff with polyphenol oxidase activity, release of VOCs, and secretion of EFN. Hook-shaped trichomes were abundantly present in four of 14 genotypes investigated, and were found only in one monophyletic group of an AFLP-based tree, thus indicating a single evolutionary origin within the species. Our findings show that different lima bean genotypes express either one of two defense systems: 1) high constitutive defense via cyanogenesis and trichomes or 2) high inducible defense via VOCs, EFN, and PPO activity"
Keywords:		"Cyanides/metabolism *Evolution, Molecular Genotype *Mechanical Phenomena Oxidation-Reduction Phaseolus/genetics/metabolism/*physiology Plant Nectar/metabolism/physiology *Plant Physiological Phenomena Polyphenols/metabolism Volatile Organic Compounds/meta;"
Notes:		"MedlineBallhorn, Daniel J Godschalx, Adrienne L Kautz, Stefanie eng 2013/02/19 J Chem Ecol. 2013 Mar; 39(3):413-7. doi: 10.1007/s10886-013-0255-6. Epub 2013 Feb 17"