Capturing the interaction types of two Bt toxins CrylAc and Cry2Ab on suppressing the cotton bollworm by using multi-exponential equations  

作　　者：Pei-Jian Shi Ji-Zhen Wei Hardev S. Sandhu Ge-Mei Liang 

机构地区：[1]Collaborative Innovation Center of Sustainable Forestry in Southem China of Jiangsu Province, Bamboo Research Institute, Nanjing Forestry University, Nanjing, China [2]State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China [3]Institute of Food and Agricultural Sciences, Everglades Research and Education Center, University of Florida, Belle Glade, USA

出　　处：《Insect Science》2016年第4期649-654,共6页昆虫科学（英文版）

基　　金：RJ. Shi received support from the National Natural Science Foundation for Young Scholars of China （No. 31400348）, the Priority Academic Program Development of Jiangsu Higher Education Institutions, and the Startup Foundation of Nanjing Forestry University （GXL038）. J.Z. Wei and G.M. Liang received support from the Key Project for Breeding Genetically Modified Organisms （2014ZX08011-002）, and the National Natural Science Foundations of China （No. 30971921, 31321004）.

摘　　要：Transgenic crops are increasingly promoted for their practical effects on suppressing certain insect pests, but all transgenic crops are not equally successful. The insect pests can easily develop resistance against single Bacillus thuringiensis （Bt） toxin trans- genic crops. Therefore, transgenic crops including two or more mixed Bt-toxins can solve this problem by delaying the resistance development and killing the majority of targeted pests before the evolution of resistance. It is important to test the controlling effects of transgenic crops including multiple mixed toxins on a particular insect pest. Previous research has checked the cross-resistance and interactions between Bt toxins CrylAc and Cry2Ab against one susceptible and four resistant strains of cotton bollworm. The results showed that independence was the main interaction type between two toxins for the susceptible strain, whereas synergism was the main interaction type for any one resistant strain. However, the optimal combinations of two toxins were not obtained. In the present study, we developed two multi-exponential equations （namely bi- and tri-exponential equations） to describe the combination effects of two Bt toxins. Importantly, the equations can provide predictions of combination effects of different continuous concentrations of two toxins. We compared these two multi-exponential equations with the generalized linear model （GLM） in describing the combination effects, and found that the bi- and tri-exponential equations are better than GLM. Moreover, the bi-exponential equation can also provide the optimal dose combinations for two toxins.Transgenic crops are increasingly promoted for their practical effects on suppressing certain insect pests, but all transgenic crops are not equally successful. The insect pests can easily develop resistance against single Bacillus thuringiensis （Bt） toxin trans- genic crops. Therefore, transgenic crops including two or more mixed Bt-toxins can solve this problem by delaying the resistance development and killing the majority of targeted pests before the evolution of resistance. It is important to test the controlling effects of transgenic crops including multiple mixed toxins on a particular insect pest. Previous research has checked the cross-resistance and interactions between Bt toxins CrylAc and Cry2Ab against one susceptible and four resistant strains of cotton bollworm. The results showed that independence was the main interaction type between two toxins for the susceptible strain, whereas synergism was the main interaction type for any one resistant strain. However, the optimal combinations of two toxins were not obtained. In the present study, we developed two multi-exponential equations （namely bi- and tri-exponential equations） to describe the combination effects of two Bt toxins. Importantly, the equations can provide predictions of combination effects of different continuous concentrations of two toxins. We compared these two multi-exponential equations with the generalized linear model （GLM） in describing the combination effects, and found that the bi- and tri-exponential equations are better than GLM. Moreover, the bi-exponential equation can also provide the optimal dose combinations for two toxins.

关 键 词：bi-exponential equation interaction MORTALITY resistance tri-exponential equation 

分 类 号：S435.622.2[农业科学—农业昆虫与害虫防治] O156.7[农业科学—植物保护]