Effects of feeding Spodoptera littoralis on lima bean leaves. II. Continuous mechanical wounding resembling insect feeding is sufficient to elicit herbivory-related volatile emission.
Herbivore feeding elicits defense responses in infested plants, including the emission of volatile organic compounds that can serve as indirect defense signals. Until now, the contribution of plant tissue wounding during the feeding process in the elicitation of defense responses has not been clear. For example, in lima bean (Phaseolus lunatus), the composition of the volatiles induced by both the insect caterpillar Spodoptera littoralis and the snail Cepaea hortensis is very similar. Thus, a mechanical caterpillar, MecWorm, has been designed and used in this study, which very closely resembles the herbivore-caused tissue damage in terms of similar physical appearance and long-lasting wounding period on defined leaf areas. This mode of treatment was sufficient to induce the emission of a volatile organic compound blend qualitatively similar to that as known from real herbivore feeding, although there were significant quantitative differences for a number of compounds. Moreover, both the duration and the area that has been mechanically damaged contribute to the induction of the whole volatile response. Based on those two parameters, time and area, which can replace each other to some extent, a damage level can be defined. That damage level exhibits a close linear relationship with the accumulation of fatty acid-derived volatiles and monoterpenes, while other terpenoid volatiles and methyl salicylate respond in a nonlinear manner. The results strongly suggest that the impact of mechanical wounding on the induction of defense responses during herbivore feeding was until now underestimated. Controlled and reproducible mechanical damage that strongly resembles the insect's feeding process represents a valuable tool for analyzing the role of the various signals involved in the induction of plant defense reactions against herbivory.
Mithöfer
Axel
A
Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany.
Wanner
Gerhard
G
Boland
Wilhelm
W
D000818:Animals; D005247:Feeding Behavior; D007814:Larva / Q000502:physiology; D027805:Phaseolus / Q000378:metabolism / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology / Q000648:ultrastructure; D012908:Snails / Q000502:physiology; D018411:Spodoptera / Q000502:physiology*; D014835:Volatilization
Plant Physiol. 2001 Jan;125(1):369-77
11154344
Planta. 2001 Dec;214(2):171-9
11800380
Annu Rev Plant Biol. 2002;53:299-328
12221978
Plant Cell Physiol. 2000 Apr;41(4):391-8
10845451
Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8399-402
11607325
Plant Physiol. 1999 Oct;121(2):325-32
10517823
Plant Biol (Stuttg). 2004 Jul;6(4):387-401
15248121
Phytochemistry. 2002 Nov;61(5):545-54
12409021
J Chem Ecol. 2004 Feb;30(2):255-71
15112723
Proc Natl Acad Sci U S A. 2004 Jun 15;101(24):8993-7
15184664
Trends Plant Sci. 2002 Feb;7(2):61-7
11832276
Plant Physiol. 2001 Feb;125(2):711-7
11161028
Arch Insect Biochem Physiol. 2001 Apr;46(4):165-74
11304750
J Chem Ecol. 1990 Feb;16(2):381-96
24263497
New Phytol. 2002 Nov;156(2):145-169
33873279
Plant Cell. 2000 May;12(5):707-20
10810145
J Chem Ecol. 1993 Mar;19(3):581-99
24248958
J Plant Growth Regul. 2000 Jun;19(2):195-216
11038228
Plant Physiol. 2004 Apr;134(4):1752-62
15051862
Science. 2001 Mar 16;291(5511):2141-4
11251117
Plant Cell. 2004 Nov;16(11):3132-47
15494554
Proc Natl Acad Sci U S A. 1995 Mar 14;92(6):2036-40
11607516
Physiol Plant. 2003 Mar;117(3):403-412
12654041
Science. 1990 Nov 30;250(4985):1251-3
17829213
Plant Physiol. 1999 Sep;121(1):153-62
10482670
Plant Physiol. 1996 Jun;111(2):487-495
12226304