Effect of transgenic Bt rice on the survival of three nontarget stored product insect pests

The effects of Bacillus thuringiensis (Bt) transgenic Ariete and Senia rice lines developed for the control of Chilo suppressalis Walker were evaluated on three nontarget stored product insect pests: the lepidopteran Plodia interpunctella (Hübner), the coleopteran Sitophilus oryzae L., and the psocid Liposcelis bostrichophila (Badonnel). Two different cry genes (cry1B and cry1Aa) under the control of a constitutive plant promoter (ubi) and a wound inducible promoter (mpi) were tested. Plodia interpunctella was unable to survive in rice semolina obtained from the two Ariete and Senia lines, which contained the ubi:cry1B gene. A reduction in S. oryzae adult progeny was observed in cultivar Senia rice containing the ubi:cry1B gene but not in cultivar Ariete rice. Moreover, a sublethal effect on S. oryzae adult progeny weight was observed in both of the rice cultivar treatments that constitutively expressed this gene. The number of L. bostrichophila emerging from Ariete rice containing the ubi:cry1B gene also was reduced. Both a reduction in the number of emerged adults and a delay in the development of P. interpunctella were observed for Ariete rice semolina containing the mpi:cry1B gene. However, no lethal or sublethal effects were observed for P. interpunctella reared on a transformed Senia rice line expressing the ubi:cry1Aa gene, suggesting possible tolerance to the toxin present in the rice grains. Although no increase in mortality was observed with S. oryzae fed ubi:cry1Aa rice, there was a sublethal effect on adult progeny weight.

This study was supported by project INIA RTA2005-00068-00-00.

Peer reviewed