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Research Project: Insect Biotechnology Products for Pest Control and Emerging Needs in Agriculture

Location: Biological Control of Insects Research

Title: Cry1Ab expression rice does not influence expression of fecundity related genes in the wolf spider Pardosa pseudoannulata

Author
item Wang, Juan - Hunan Agricultural University
item Peng, Yuan-de - Chinese Academy Of Agricultural Sciences
item Chao, He - Central South University
item Wei, Bao-yang - Hunan Agricultural University
item Liang, Yun-shan - Hunan Agricultural University
item Yang, Yun-shan - Hunan Agricultural University
item Wang, Zhi - Hunan Agricultural University
item Stanley, David
item Song, Qisheng - University Of Missouri

Submitted to: Gene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2016
Publication Date: 7/22/2016
Citation: Wang, J., Peng, Y., Chao, H., Wei, B., Liang, Y., Yang, Y., Wang, Z., Stanley, D.W., Song, Q. 2016. Cry1Ab expression rice does not influence expression of fecundity related genes in the wolf spider Pardosa pseudoannulata. Gene. doi:10.1016/j.gene.2016.07.041.

Interpretive Summary: Use of classical insecticides has introduced severe problems in agricultural and environmental sustainability. Two of most pressing problems are the increasing ability of pest insects to resist classical insecticides and the negative influence of insecticides on ecosystems. One approach to reduce the environmental insecticide load is based on the concept of expressing insecticidal toxic proteins from an insect-killing bacterium in crop plants, known as Bt-crops. This modern approach to insect control is growing at the global level. Nonetheless, continued studies on the relative to movement of Bt-toxins in agroecosystems and their impacts on non-target arthropods remain necessary. To help resolve this need, we investigated the movement of a Bt toxin from rice plants to rice pest insects and on to predatory spiders. In this paper we report that Bt toxins have potential to move through agroecosystem food webs. To test for possible effects of the Bt toxin at the molecular level, we investigated the influence of spiders acquiring Bt toxins on genes related to spider fecundity. We found no changes in expression of spider genes related to fecundity. This new research will be directly useful to scientists working to improve the use of Bt crops. The ensuing improved methods will benefit a wide range of agricultural producers, and people who rely on agricultural products, by supporting the long-term sustainability of agriculture.

Technical Abstract: The impact of Bacillus thuringiensis (Bt) toxin proteins on the arthropod assemblages in rice agroecosystems, including non-target predatory arthropods, has been well documented. However, the influence of Bt toxins on predators remains understudied at the cellular and molecular levels. Here, we investigated the potential effects of Cry1Ab expressing rice on fecundity of the wolf spider, Pardosa pseudoannulata, and underlining molecular mechanisms. The results indicated that brown planthoppers (BHPs) reared on Cry1Ab-expressing rice accumulated the Cry toxin and reproductive parameters (pre-oviposition period, post- parturition stage, number of eggs and egg hatching rate) of the spiders that consumed BPHs reared on Bt rice were not different from those that consumed BPHs reared on the non-Bt control rice. Vitellin (Vt) stability assessment revealed that accumulated Cry1Ab did not influence several Vt parameters, including stored energy and amino acid composition. These results are based on a single generation. We considered the possibility that the Cry toxins exert their influence on beneficial predators via more subtle effects detectable at the molecular level in terms of gene expression, rather than whole-organismal reproductive potential. This led us to transcriptome analysis to detect differentially expressed genes in the ovaries of spiders exposed to dietary Cry1Ab and their counterpart control spiders. Eight genes, associated with vitellogenesis, vitellogenin receptor activity and vitelline membrane formation were not differentially expressed between ovaries from the treated and control spiders, confirmed by qPCR analysis. We infer that dietary Cry1Ab expressing rice does not influence fecundity, nor expression levels of (Vt) associated genes of P. pseudoannulata.