Belowground chemical signaling in maize: When simplicity rhymes with efficiency
| Résumé |
Maize roots respond to feeding by larvae of the beetle Diabrotica
virgifera virgifera by releasing (E)-beta-caryophyllene. This
sesquiterpene, which is not found in healthy maize roots, attracts
the entomopathogenic nematode Heterorhabditis megidis. In sharp
contrast to the emission of virtually only this single compound by
damaged roots, maize leaves emit a blend of numerous volatile
organic compounds in response to herbivory. To try to explain this
difference between roots and leaves, we studied the diffusion
properties of various maize volatiles in sand and soil. The best
diffusing compounds were found to be terpenes. Only one other
sesquiterpene known for maize, alpha-copaene, diffused better than
(E)-beta-caryophyllene, but biosynthesis of the former is far more
costly for the plant than the latter. The diffusion of
(E)-beta-caryophyllene occurs through the gaseous rather than the
aqueous phase, as it was found to diffuse faster and further at low
moisture level. However, a water layer is needed to prevent complete
loss through vertical diffusion, as was found for totally dry sand.
Hence, it appears that maize has adapted to emit a readily
diffusing and cost-effective belowground signal from its
insect-damaged roots. |
| Mots-clés |
belowground tritrophic interactions, (E)-beta-caryophyllene, roots, diffusion, entomopathogenic nematodes, indirect plant defense, plant-insect interactions, WESTERN CORN-ROOTWORM, SOLID-PHASE MICROEXTRACTION, PLANT VOC, EMISSIONS, ENTOMOPATHOGENIC NEMATODES, VOLATILE ISOPRENOIDS, SECONDARY, METABOLISM, BIOLOGICAL-CONTROL, MOLECULAR-BIOLOGY, INDUCED RESPONSES, PARASITIC WASPS |
| Citation | Hiltpold, I., & Turlings, T. (2008). Belowground chemical signaling in maize: When simplicity rhymes with efficiency. Journal of Chemical Ecology, 34(5), 628-635. |
| Type | Article de périodique (Anglais) |
| Date de publication | 2008 |
| Nom du périodique | Journal of Chemical Ecology |
| Volume | 34 |
| Numéro | 5 |
| Pages | 628-635 |