High nitrogen in maize enriches gut microbiota conferring insecticide tolerance in lepidopteran pest Spodoptera litura

Lin Hu; Zhongxiang Sun; Cuicui Xu; Jie Wang; Azim U Mallik; Chengzhen Gu; Daoqian Chen; Long Lu; Rensen Zeng; Yuanyuan Song

doi:10.1016/j.isci.2021.103726

High nitrogen in maize enriches gut microbiota conferring insecticide tolerance in lepidopteran pest Spodoptera litura

iScience. 2022 Jan 2;25(1):103726. doi: 10.1016/j.isci.2021.103726. eCollection 2022 Jan 21.

Authors

Lin Hu^{1

2}, Zhongxiang Sun¹, Cuicui Xu³, Jie Wang¹, Azim U Mallik⁴, Chengzhen Gu³, Daoqian Chen¹, Long Lu¹, Rensen Zeng^{1

3}, Yuanyuan Song¹

Affiliations

¹ Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
² Key Laboratory of Beibu Gulf Environment Change and Resources Utilization of Ministry of Education, Nanning Normal University, Nanning 530001, China.
³ State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
⁴ Department of Biology, Lakehead University, Thunder Bay, ON P7B 5E1, Canada.

Abstract

Abuse of chemical fertilizers and insecticides has created many environmental and human health hazards. We hypothesized that high nitrogen (N) in crops changes insect gut microbiota leading to enhanced insecticide tolerance. We investigated the effect of high N in maize on gut microbiota and insecticide tolerance of the polyphagous pest Spodoptera litura. Bioassays showed that high N applied in both maize plants and artificial diets significantly enhanced larval growth but reduced larval sensitivity to the insecticide methomyl. High N promoted the gut bacterial abundance in the genus Enterococcus. Inoculation with two strains (E. mundtii and E. casseliflavus) isolated from the larval guts increased larval tolerance to methomyl. Incorporation of antibiotics in a high-N diet increased the larval sensitivity to methomyl. These findings suggest that excessive application of N fertilizer to crops can increase insecticide tolerance of insect pests via changing gut microbiota, leading to increased use of insecticides worldwide.

Keywords: Interaction of plants with organisms; Microbiology parasite; Microbiome; Omics.