| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4507999 | Crop Protection | 2006 | 5 Pages |
Insecticidal toxins produced by Bacillus thuringiensis (Bt toxins) have been widely used in plant protection in two different ways: spraying of bacterial Bt toxin formulations over plants and production of the toxins in planta by expressing the genes encoding for the proteins. In the second strategy, only the transgenic plants themselves are protected. We have now broadened the application of insect-resistant transgenics in a third scenario: protection of other crops that theoretically could be recalcitrant to DNA transformation. Using cabbage as a model crop well known to be susceptible to many pests, the Bt toxin Cry1Ab was first produced in transgenic rice (Oryza sativa) plants and then was applied to the leaves of cabbage (Brassica juncea) to test its toxicity against larvae of Pieris rapae. Seventy-eight to 100% larval mortality was observed for different instar larvae. Furthermore, no-choice feeding of the larvae on the Bt toxin-treated cabbage leaves had adverse effects on the oviposition rates and egg hatchability of surviving adult moths. Bt toxin-treated larvae had 30% and 46% lower moth emergence rates than their control counterparts. Female moths from the Bt toxin-treated larvae had significantly reduced egg production, 15.1 eggs per female versus the control 326.3 eggs, and lower hatching rates, 3.1% versus 33.8% in the control. Since long term stability is a key factor contributing to the potential of ex situ application of plant-made biocides, Cry1Ab protein stability was assessed in the detached rice leaf tissue. The toxin was found to be stable over a 5-month storage period, declining 31.7% and 20% from the initial content when stored at 4 and 37 °C, respectively.
