Linking Primary and Secondary Metabolism A Mechanistic Hypothesis for how Elevated CO2 Modulates Defenses

GOG, L.; ZAVALA, J. A.; DELUCIA E.H.

The Biology of Plant-Insect Interactions: A Compendium for the Plant Biotechnologist

CRC Press

Año: 2018; p. 93 - 112

Rising atmospheric CO2 affects insect herbivory by altering both theprimary and secondary metabolism of plants (Zavala et al. 2013). In termsof primary metabolism, the portion of plant physiology immediatelyconcerned with growth, elevated CO2 increases the rate of photosynthesisand thus the accumulation of starch in leaves. The consequences of thiseffect on insect feeding behavior are two-fold: With a more concentratedsupply of carbohydrates, insect herbivores are provided with chemicalenergy to increase their rates of feeding (Lincoln et al. 1986; for review seeZavala et al. 2013). At the same time, increased starch content dilutes foliarnitrogen and thus obliges insect herbivores to compensate their nitrogenrequirements by ingesting more leaf tissue (Lincoln et al. 1986; for reviewsee Zavala et al. 2013). Meanwhile, the effects of elevated CO2 on plantsecondary metabolism?the portion of plant physiology responsiblefor mediating ecological interactions through chemical defense?arecomparatively resistant to generalization. The source of uncertainty inunderstanding how elevated CO2 influences insect feeding behavior restsin the regulatory connection between primary and secondary metabolism.