Combined influence of Bt rice and rice dwarf virus on biological parameters of a non-target herbivore, Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae)

Authors: WANG, QIANJIN - Zheijiang University; HAN, NAISHUN - Zheijiang University; DANG, CONG - Zheijiang University; LU, ZENGBING - Zheijiang University; WANG, FANG - Zheijiang University; YAO, HONGWEI - Zheijiang University; PENG, YUFA - Zheijiang University; Stanley, David; YE, GONG-YIN - Zheijiang University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/2017
Publication Date: 7/28/2017
Citation: Wang, Q., Han, N., Dang, C., Lu, Z., Wang, F., Yao, H., Peng, Y., Stanley, D.W., Ye, G. 2017. Combined influence of Bt rice and rice dwarf virus on biological parameters of a non-target herbivore, Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae). PLoS One. https://doi.org/10.1371/journal.pone.0181258.
DOI: https://doi.org/10.1371/journal.pone.0181258

Interpretive Summary: Successful insect pest management programs are essential to sustainable large-scale production of safe and affordable foods globally. Classical insecticides are effective components of pest management programs, however, issues of environmental quality and insect resistance to insecticides drive research into alternative pest management technologies. One successful technology is deploying crops expressing insecticidal toxins, known as Bt toxins. Bt crops facilitate tremendous reductions in use of chemical insecticides. The problem, however, is the ecological effects of Bt crops must be thoroughly researched for their long-term safety before they can be released for wide-spread use. Although many aspects of the safety of Bt rice has been researched, we identified an additional potential issue: All rice cropping systems include rice pathogenic viruses. We conducted the first laboratory investigation into possible unexpected outcomes of the influence of Bt rice coupled with rice plant infection by a rice pathogenic virus. We found viral-infected rice plants do not pose additional risks associated with deploying Bt rice into agroecosystems that also support rice plant pathogens. This new research will be directly useful to scientists who are working to improve the efficacy of Bt crops. The ensuing improved insect pest control measures will benefit a wide range of agricultural producers and consumers by supporting the long-term sustainability of agriculture.

Technical Abstract: The advent of genetically modified (GM) Bt rice creates the possibility of interactions among Bt crops, crop pathogens and non-target herbivores. In particular, information on how pathogen-infected Bt-expressing plants will influence non-target herbivores is necessary to predict the sustainability of GM cropping systems. Laboratory bioassays were conducted to evaluate the potential combined impacts of rice dwarf virus (RDV) and two Bt rice lines, T1C-19 (Cry1C) and T2A-1 (Cry2A), on non-target green rice leafhopper (GRLH), Nephotettix cincticeps (Uhler) (Hemiptera: Cicadellidae). In the first experiment, GRLHs feeding preference tests on Bt rice lines compared to a parental control rice line, MH63, were conducted. As rice plants were uninfected with RDV, GRLHs generally preferred the control MH63 line over the two Bt lines during the initial 8 h, with no significant preference during the following 64 h. As rice plants were infected with RDV, there were no clear preferences between the Bt rice lines and the control MH63 line. In the second experiment, we assessed the combined influence of RDV-infection status and Bt rice lines on GRLH biological parameters. Egg duration, adult weights, and male adult longevity were significantly affected on RDV-infected Bt rice. Other parameters, egg hatching rate, nymph survival and fecundity were not significantly influenced. We infer that interaction effect among two testing Bt rice lines and RDV will not lead to enlarged pest populations, thus demonstrating that growing these two Bt rice lines will poses negligible risk to GRLH in sustainable rice agroecosystems. Long-term field experiments to monitor the population dynamics of GRLHs at large scale need to be carried out to confirm the current results.