Glucosinolate responses of oilseed rape, mustard and kale to mechanical wounding and infestation by cabbage stem flea beetle (Psylliodes chrysocephala)

Abstract

Summary Mechanical wounding of the petioles of six laboratory‐grown rapeseed (Brassica napus) cultivars induced physiological changes in the plant, markedly affecting the levels of individual glucosinolates. Greatest increases were observed for the indole glucosinolates, glucobrassicin and neoglucobrassicin. Such changes were usually associated with large decreases in the levels of aliphatic glucosinolates. The total glucosinolate content of the wounded plant was thus a reflection of these two opposing trends and wounding produced a greater relative indole glucosinolate content in this total figure. Thus increasing wounding was associated with an increase in indole glucosinolates and a decrease in aliphatic compounds. Infestation of field‐ and laboratory‐grown rapeseed with cabbage stem flea beetle (Psylliodes chrysocephala) produced similar effects, which were observed in various parts of the plant. Differences in response between field‐ and laboratory‐grown infested plants are attributed to the different physiological ages of the harvested material. Laboratory‐grown kale and mustards also showed wound‐induced glucosinolate changes. The kale, cv. Fribor, produced elevated levels of both indoles and aliphatics after wounding. Total glucosinolate content in the mustards, which, unlike rape and kale, normally contain only traces of indole glucosinolates in the unstressed state, was increased following wounding. This was, however, not associated with elevated levels of indole glucosinolates, but with accumulation of aliphatic (Brassica nigra, B. juncea) and aromatic (Sinapis alba) glucosinolates. The significance of these findings is discussed.

A Wound- and Methyl Jasmonate-Inducible Transcript Coding for a Myrosinase-Associated Protein with Similarities to an Early Nodulin

“…Also, so far we have not investigated the presence of myrosinase complexes in homogenates of vegetative B. napus tissues. However, a wound-induced increase in MyAP-related proteins might represent an indirect way to modify the myrosinase activity, perhaps to bias the activity toward the glucosinolates that are induced by wounding (Koritsas et al, 1991;Bodnaryk, 1992). The preformed myrosinase enzymes exhibited the least activity toward these wound-induced glucosinolates (James and Rossiter, 1991).…”

Defence mechanisms of Brassicaceae: implications for plant-insect interactions and potential for integrated pest management. A review

“…They have been recognised as a class of natural pesticides since they exhibit toxic or repellent effects, by which they establish a significant defence mechanism to protect Brassica plants against pests and diseases (Mithen, 1992;Zukalová and Vašák, 2002). Glucosinolate levels and proportions of individual glucosinolate compounds have been demonstrated to be altered due to the damage caused by several insect pests (Koritsas et al, 1991;Bodnaryk, 1992;Hopkins et al, 1998). The glucosinolate concentration can increase in response to herbivore feeding, and this high level of glucosinolates can affect both generalist and specialist herbivores, and glucosinolates can be equally effective as stimulants as well as deterrents (Bodnaryk, 1992;Bartlet et al, 1999;Li et al, 2000;Rask et al, 2000;Agrawal and Kurashige, 2003;Kuśnierczyk et al, 2007Kuśnierczyk et al, , 2008Gols et al, 2008a).…”

Divergent selection for secondary metabolites between wild populations of Brassica oleracea and its implications for plant-herbivore interactions

“…The differences in indole glucosinolates did not have a genetic basis but were caused by seasonal and other environmental variation. Herbivores, pathogens and physical damage are known to induce indole glucosinolates (Koritsas et a!., 1989(Koritsas et a!., , 1991Doughty et a!., 1991;Macfarlane Smith et a!. 1991;Bodnaryk, 1992;Birch et a!., 1994).…”