Journal of Chemical Ecology (2010) 36, 35-45

Bridget F. O'Neill, Arthur R. Zangerl, Orla Dermody, Damla D. Bilgin, Clare L. Casteel, Jorge A. Zavala, Evan H. DeLucia and May R. Berenbaum (2010)
Impact of elevated levels of atmospheric CO₂ and herbivory on flavonoids of soybean (Glycine max Linnaeus)
Journal of Chemical Ecology 36 (1), 35-45
Abstract: Atmospheric levels of carbon dioxide (CO₂) have been increasing steadily over the last century. Plants grown under elevated CO₂ conditions experience physiological changes, particularly in phytochemical content, that can influence their suitability as food for insects. Flavonoids are important plant defense compounds and antioxidants that can have a large effect on leaf palatability and herbivore longevity. In this study, flavonoid content was examined in foliage of soybean (Glycine max Linnaeus) grown under ambient and elevated levels of CO₂ and subjected to damage by herbivores in three feeding guilds: leaf skeletonizer (Popillia japonica Newman), leaf chewer (Vanessa cardui Linnaeus), and phloem feeder (Aphis glycines Matsumura). Flavonoid content also was examined in foliage of soybean grown under ambient and elevated levels of O₃ and subjected to damage by the leaf skeletonizer P. japonica. The presence of the isoflavones genistein and daidzein and the flavonols quercetin and kaempferol was confirmed in all plants examined, as were their glycosides. All compounds significantly increased in concentration as the growing season progressed. Concentrations of quercetin glycosides were higher in plants grown under elevated levels of CO₂. The majority of compounds in foliage were induced in response to leaf skeletonization damage but remained unchanged in response to non-skeletonizing feeding or phloem-feeding. Most compounds increased in concentration in plants grown under elevated levels of O₃. Insects feeding on G. max foliage growing under elevated levels of CO₂ may derive additional antioxidant benefits from their host plants as a consequence of the change in ratios of flavonoid classes. This nutritional benefit could lead to increased herbivore longevity and increased damage to soybean (and perhaps other crop plants) in the future.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): May R. Berenbaum, Bridget F. O'Neill, Jorge A. Zavala

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Popillia japonica	Soybean (Glycine max)
	Aphis glycines	Soybean (Glycine max)
	Vanessa cardui	Soybean (Glycine max)