Phenolic compounds that confer resistance to spruce budworm

Abstract

Phenolic compounds are apparently important in the defence mechanisms of conifers. To test the hypothesis that phenolic compounds in resistant white spruce [Picea glauca (Moench) Voss (Pinaceae)] impart resistance against spruce budworm [Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae)], we performed aqueous extractions of current-year shoots of white spruce that were tolerant of varying levels of budworm defoliation. High-performance liquid chromatographic profiles of water extracts of P. glauca needles differed between resistant and susceptible trees. Further nuclear magnetic resonance analyses identified two phenolic glucosides in susceptible white spruce, picein [3-(b-D-glucosyloxy)-hydroxy-acetophenone] and pungenin [3-(b-D-glucosyloxy)-4-hydroxy-acetophenone], and two phenolics in resistant white spruce, pungenol (3¢,4¢-hydroxy-acetophenone) and piceol (4¢-hydroxyacetophenone). We focused on the performance of spruce budworm when piceol and pungenol were added to the diet. These two compounds significantly reduced larval survival, retarded development, and reduced pupal mass. Food consumption by sixth-instar spruce budworms was affected by a combination of the phenolic compounds. These results suggest that the two phenolic compounds reduce the pressure of spruce budworm herbivory on specific host tree phenotypes. Thus, the mechanism of defence in P. glauca apparently reflects a strategy of constitutive resistance.

Two new iridoids from selectedPenstemonspecies – antimicrobial activity

“…Moreover, three phenylpropanoid glucosides: martynoside (13) (Teborg & Junior 1989) in a mixture with cis-martynoside (14) (Skrzypek et al 1999) and verbascoside (15) (Gvazava & Kikoladze 2007), and two acetophenone derivatives, namely picein (16) (Delvas et al 2011) and androsin (17) (De Rosa et al 1996) were identified in this plant.…”

Comparative ecology of conifer-feeding spruce budworms (Lepidoptera: Tortricidae)

“…However, these are normal, seasonal changes in the physical characteristics of the foliage, whereas most of the studies of host quality examine plant-chemical and physiological relationships to identify either constitutive or induced mechanisms of resistance (Clancy 2002). For good experimental reasons, this work often uses artificial diet containing extracted, controlled nutritional supplements (e.g., Albert and Bauce 1994;Delvas et al 2011) and so remove the seasonal physical characteristics of intact foliage. Overall results show that aside from the dominant importance of nitrogen, variability in host-plant chemistry has minor negative effects on the performance of budworms and there is little evidence of induced plant responses with significant negative feedbacks to population rates of change (Mattson et al 1991).…”

Association genetics of phenolic needle compounds in Norway spruce with variable susceptibility to needle bladder rust

“…In Norway spruce ( Picea abies (L.) H.Karst), several phenolic compounds were found to be associated with resistance to insects, herbivory and pathogen attack, or showed increased concentration following infection and wounding (Lindberg et al 1992; Brignolas et al 1995; Bahnweg et al 2000; Evensen et al 2000; Delvas et al 2011; Hammerbacher et al 2011, 2013; Fossdal et al 2012; Schiebe et al 2012; Krajnc et al 2014). Furthermore, attempts have been made to use phenolic metabolites as predictors of spruce resistance to insect and microbial attack (Lieutier et al 1997, 2003; Brignolas et al 1998).…”