SNF1-related kinases allow plants to tolerate herbivory by allocating carbon to roots

• DOI: 10.1073/pnas.0602316103
• Publication Date: 2006-08-16T02:48:21Z
• Authors: Jens Schwachtje; Peter E. H. Minchin; Sigfried Jahnke; Joost T. van Dongen; Ursula Schittko; Ian T. Baldwin
• Keywords: Protein-Serine-Threonine Kinases: metabolism; Nicotiana; 0301 basic medicine; info:eu-repo/classification/ddc/000; Molecular Sequence Data; Protein Serine-Threonine Kinases; Plant Roots: metabolism; Plant Roots; 03 medical and health sciences; Animals; Tobacco: enzymology; carbon-11; plant-herbivore interactions; Plant Roots: growth & development; 2. Zero hunger; tolerance; Tobacco: growth & development; Feeding Behavior; 15. Life on land; Protein-Serine-Threonine Kinases; Plants, Genetically Modified; Protein-Serine-Threonine Kinases: genetics; Carbon; J; defense; Tobacco: metabolism; Tobacco: genetics; Carbon: metabolism

Herbivore attack elicits costly defenses that are known to decrease plant fitness by using resources that are normally slated for growth and reproduction. Additionally, plants have evolved mechanisms for tolerating attack, which are not understood on a molecular level. Using 11 C-photosynthate labeling as well as sugar and enzyme measurements, we found rapid changes in sink–source relations in the annual Nicotiana attenuata after simulated herbivore attacks, which increased the allocation of sugars to roots. This herbivore-induced response is regulated by the β-subunit of an SnRK1 (SNF1-related kinase) protein kinase, GAL83, transcripts of which are rapidly down-regulated in source leaves after herbivore attack and, when silenced, increase assimilate transport to roots. This C diversion response is activated by herbivore-specific elicitors and is independent of jasmonate signaling, which regulates most of the plant's defense responses. Herbivore attack during early stages of development increases root reserves, which, in turn, delays senescence and prolongs flowering. That attacked GAL83-silenced plants use their enhanced root reserves to prolong reproduction demonstrates that SnRK1 alters resource allocation so that plants better tolerate herbivory. This tolerance mechanism complements the likely defensive value of diverting resources to a less vulnerable location within the plant.