This paper is relevant to the impact areas in the following areas:
| Crops | Soybean |
| Traits | Insect Res. (BT), Insect Resistance |
| Countries | Not country-specific |
| Regions | Not region-specific |
| Tags | Agrotis ypsilon, Helicoverpa armigera, Spodoptera exigua, Spodoptera litura |
Background
Two transgenic lines of the soybean Glycine max, ‘MON87701’ expressing the Cry1Ac protein, and ‘MON87701RR2Y’ expressing Cry1Ac + EPSPS proteins were evaluated for their resistance to four lepidopteran pests in the laboratory using detached-leaf bioassays throughout the soybean growth seasons (before anthesis, during anthesis and after anthesis) in China. Enzyme-linked immunosorbent assays (ELISA) were used to monitor the Cry1Ac expression in soybean leaves.
Results
The bioassay results revealed that both transgenic soybean lines exhibited significantly high resistance against Helicoverpa armigera(Hübner) throughout the soybean growing seasons. The survival rates of H. armigera larvae ranged from 5.4-24.4% when feeding on the transgenic soybean leaves that were significantly lower than those when feeding on control leaves with survival rates of 71.1-94.9%. Limited resistance were found for both transgenic soybean lines against Spodoptera litura (Fabricius), although the survival rates and weight of S. litura larvae as well as female fecundity were significantly decreased when feeding on Bt soybean leaves compared to those feeding control leaves. In contrast, both transgenic soybean lines provide almost no resistance to Spodoptera exigua (Hübner) and Agrotis ypsilon (Rottemberg). Cry1Ac expression in the leaves of both transgenic soybean lines were relatively stable throughout the soybean growing season with a peak occurring at V6-8 and V11-12 before anthesis. The ELISA results were positively correlated with the results from the insect bioassays.
Conclusions
The results show that while Cry1Ac-expressing Bt soybeans may provide good protection against H. armigera, alternative control measures are required to manage S. exigua, S. litura, and A. ypsilon.
Expression of Cry1Ac in transgenic Bt soybean lines and their efficiency in controlling lepidopteran pests (held on an external server, and so may require additional authentication details)
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