Belowground herbivore tolerance involves delayed overcompensatory root regrowth in maize

Authors: ROBERT, CHRISTELLE - University Of Bern; SCHIRMER, STEFANIE - Max Planck Institute For Biogeochemistry; Barry, Julie; French, Bryan; Hibbard, Bruce; GERSHENZON, JONATHAN - Max Planck Institute For Biogeochemistry

Submitted to: Entomologia Experimentalis et Applicata
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2015
Publication Date: 9/16/2015
Publication URL: http://handle.nal.usda.gov/10113/61491
Citation: Robert, C.A., Schirmer, S., Barry, J.M., French, B.W., Hibbard, B.E., Gershenzon, J. 2015. Belowground herbivore tolerance involves delayed overcompensatory root regrowth in maize. Entomologia Experimentalis et Applicata. 157:113-120.

Interpretive Summary: Many plants can tolerate insect feeding on above-ground tissue by rapid regrowth of leaves. Several studies indicate that plants can re-allocate resources to the above ground parts such as stems for later root regrowth when insects are feeding on below-groud parts, but the mechanism of this remains poorly understood. We investigated the timing and extent of root regrowth of tolerant and susceptible maize lines when the roots were fed upon by the western corn rootworm in the laboratory and the field. Tolerant maize plants that were infested with the western corn rootworm produced more root biomass than susceptible plants and even over compensated for the lost roots. Furthermore, the tolerant lines slowed growth of new roots significantly earlier than the susceptible lines after insect feeding, which enabled them to save resources for regrowth until after insect feeding had ceased. Therefore, both timing and the extent of root regrowth may impact plant tolerance to root herbivory. Increased knowledge of tolerance and resistance to western corn rootworm larval feeding could lead to management options for this major pest.

Technical Abstract: Plants can tolerate leaf-herbivore attack through metabolic reconfigurations that allow for the rapid regrowth of lost leaves. Several studies indicate that root-attacked plants can re-allocate resources to the above ground parts. However, the connection between tolerance and root regrowth remains poorly understood. We investigated the timing and extent of root regrowth of tolerant and susceptible maize lines attacked by the western corn rootworm Diabrotica virgifera in the laboratory and the field. Infested tolerant maize plants produced more root biomass than susceptible plants and even over compensated for the lost roots. Furthermore, the tolerant plants stopped growing new roots significantly earlier than the susceptible lines, which may have enabled them to escape root attack by starving out the herbivores and by saving resources for regrowth after the attack had ceased. We conclude that both timing and the extent of regrowth may determine plant tolerance to root herbivory.