Age-related increase in levels of insecticidal protein in the progenies of transgenic oilseed rape and its efficacy against a susceptible strain of diamondback moth

Wei, W., Schuler, T.H., Clark, S.J., Stewart, C.N. and Poppy, G.M. (2005) Age-related increase in levels of insecticidal protein in the progenies of transgenic oilseed rape and its efficacy against a susceptible strain of diamondback moth. Annals of Applied Biology, 147 (3), 227-234. (doi:10.1111/j.1744-7348.2005.00024.x).

Abstract

Many crops transformed with insecticidal genes isolated from Bacillus thuringiensis (Bt) show resistance to targeted insect pests. The concentration of Bt endotoxin proteins in plants is very important in transgenic crop efficacy and risk assessment. In the present study, changes in levels of CrylAc protein in the leaves of transgenic Bt oilseed rape (Brassica napus) carrying a Bt crylAc gene under the control of the cauliflower mosaic virus 35S promoter were quantified during vegetative growth by enzyme-linked immunosorbent assay. Plants were grown in a glasshouse, sampled at 2, 4, 5 and 6 weeks, and the concentration of CrylAc was quantified in basal, top and previous top leaves. The mean concentration differed between sowing dates when CrylAc concentration was expressed as ng g-1 fresh leaf weight but not when expressed as ng mg-1 total soluble protein. It was demonstrated that CrylAc concentration increased significantly as the leaf aged, while the total soluble plant protein decreased significantly. Levels of CrylAc were therefore higher in leaves at the base of the plants than in leaves close to the growing point. However, even young leaves with very low CrylAc concentrations caused high mortality in the larvae of a CrylAc-susceptible laboratory strain of the diamondback moth. The feeding area of leaves consumed by larvae in vivo and in situ was similar. Leaf damage caused by sampling (i.e. artificially) or by feeding of larvae did not affect the levels of CrylAc in the leaves under the experimental conditions in this study.

This record has no associated files available for download.

Contributors

Download statistics