|San, Xiao - Hubei University|
|Yan, Miao-jun - Hubei University|
|Wang, Man-qun - Hubei University|
Submitted to: Ecotoxicology and Environmental Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2015
Publication Date: 7/3/2015
Citation: San, X., Yan, M., Zhang, A., Wang, M. 2015. TRANSGENIC CRYLC* GENE ROUGH RICE LINE TIC-19 DOES NOT CHANGE THE HOST PREFERENCES OF THE NON-TARGET STORED PRODUCT PEST, RHYZOPERTHA DOMINICA (FABRICIUS) AND ITS PARASITOID WASP, ANISOPTEROMALUS CALANDRAE. Ecotoxicology and Environmental Safety. 120:449-456.
Interpretive Summary: Rough rice grains are one of the most important food crops in the world. Many insect pests attack and damage rice plants and substantially reduce yields. In order to control insect pests affecting rice, transgenic Bt rice lines have been developed, which benefit growers and environment by greatly reducing the need for chemical pesticides. However, it is unknown if these transgenic Bt rice affect non-target insect pests and their natural enemies during rice storage. In this study, host preferences of one main beetle pest of rice and its natural enemy, a parasitic wasp species, were studied by means of behavior choice assays and gas chromatography, as well as electronic nose and tongue analyses. Our results demonstrated that genetic modification of rice may affect the grain’s volatile emissions; however, the difference in kind and degree of volatile emissions are dependent on the plant species. Host preferences of the non-target beetle pest and its natural enemy were not changed due to the introduction of specific insect toxins in rice. Therefore, rice beetle pests are likely to remain under regular biological control during Bt rough rice storage. This information will help the farmers and agricultural companies to efficiently control non-target insect pests during storage of transgenic Bt crops.
Technical Abstract: Rough rice grains are often stored for extended periods before they are used or consumed. However, during storage, the rough rice is vulnerable to insect infestation, resulting in significant economic loss. Previous studies have shown that volatile cues, physical characteristics, and taste chemicals on the grains could be the important key behavior factors for storage insect pests to locate the hosts and select oviposition sites. It is also well known that the transgenic Bt rough rice line T1C-19, which expresses a cry1C* gene, has a high resistance to Lepidoptera pests. However, there were no evidences to show the consequences of host preference for non-target insect pests after growing Bt transgenic rice. In this study, the potential key factors of Bt rough rice were investigated for their impacts on the behaviors of non-target pest lesser grain borer Rhyzopertha dominica, the main beetle pest of grain and its parasitic wasps Anisopteromalus calandrae, the natural enemy of the beetle. Both electronic nose and electronic tongue analyses showed that the parameters of Bt rough rice were analogous to those of the non-Bt rough rice. The volatile profiles of Bt and non-Bt rough rice examined by gas chromatographic mass spectrometry (GC-MS) were similar. For most volatile compounds, there were no significantly quantitative differences between Bt and non-Bt rough rices. The densities of sclereids and trichomes on the rough rice husk surface were statistically equal in Bt and non-Bt rough rices. The non-target pest, R. dominica, and its parasitoid wasp, A. calandrae, were attracted to both rough rices and could not distinguish the transgenic T1C-19 from the isogenic rough rice. These results demonstrated that Bt rough rice has no negative impacts on the host preference behaviors of non-target stored product pest R. dominica and its parasitoid A. calandrae.