Broccoli and turnip plants display contrasting responses to belowground induction by Delia radicum infestation and phytohormone applications.
Induced responses to insect herbivory are a common phenomenon in the plant kingdom. So far, induced responses have mostly investigated in aerial plant parts. Recently it was found that root herbivore may also elicit both local and systemic responses affecting aboveground herbivores and their natural enemies. Using broccoli (Brassica oleracea subsp. italica L.) and turnip (Brassica rapa subsp. rapa L.), two cultivated brassicaceaous plants differing in their chemistry and morphology, we analysed the local and systemic induced responses triggered by Delia radicum L. damage, JA and SA application. We also assessed whether the root induction treatments affected D. radicum larval performance. Both D. radicum damage and JA induced changes in glucosinolate and sugar content as well as affected D. radicum performance, while SA application did not. Despite the uniform chemical responses, the effect on larval performance on broccoli and turnip plants was very different. On broccoli, JA root treatment reduced herbivore performance, whereas in turnips the same treatment enhanced it. JA- and D. radicum-induced responses followed similar patterns, which suggests that the JA signalling pathway is involved in root-induced responses to larval feeding. Glucosinolate induction cannot fully explain the differences found in the performance of D. radicum on the different species. Changes in other resistance factors might significantly contribute to the induced resistance in these brassicaceaeous species as well.
UMR 1099 BiO3P, INRA, Agrocampus Ouest, University of Rennes Campus Scientifique de Beaulieu - Bât 25, 4 ème Avenue du Général Leclerc, 35042 Rennes Cedex, France. pierreprisca@yahoo.fr
Prisca S
PS
Pierre
Sébastien
S
Dugravot
Anne-Marie
AM
Cortesero
Denis
D
Poinsot
Ciska E
CE
Raaijmakers
Hany M
HM
Hassan
Nicole M
NM
van Dam
D000818:Animals; D001937:Brassica / Q000378:metabolism*; D029688:Brassica napus / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism; D004175:Diptera / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D005961:Glucosinolates / Q000378:metabolism*; D060434:Herbivory / Q000187:drug effects / Q000502:physiology*; D007814:Larva; D054883:Oxylipins / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D020156:Salicylic Acid / Q000378:metabolism
D003517:Cyclopentanes; D005961:Glucosinolates; D054883:Oxylipins; C011006:jasmonic acid; D020156:Salicylic Acid