Microbiome variation correlates with the insecticide susceptibility in different geographic strains of a significant agricultural pest, *Nilaparvata lugens*

Microbiome-mediated insecticide resistance is an emerging phenomenon found in insect pests. However, microbiome composition can vary by host genotype and environmental factors, but how these variations may be associated with insecticide resistance phenotype remains unclear. In this study, we compared different field and laboratory strains of the brown planthopper Nilaparvata lugens in their microbiome composition, transcriptome, and insecticide resistance profiles to identify possible patterns of correlation. Our analysis reveals that the abundances of core bacterial symbionts are significantly correlated with the expression of several host detoxifying genes (especially NICYP6ER1, a key gene previously shown involved in insecticides resistance). The expression levels of these detoxifying genes correlated with N. lugens insecticide susceptibility. Furthermore, we have identified several environmental abiotic factors, including temperature, precipitation, latitude, and longitude, as potential predictors of symbiont abundances associated with expression of key detoxifying genes, and correlated with insecticide susceptibility levels of N. lugens. These findings provide new insights into how microbiome-environment-host interactions may influence insecticide susceptibility, which will be helpful in guiding targeted microbial-based strategies for insecticide resistance management in the field.

Yunhua Zhang, Tingwei Cai, Maojun Yuan, Zhao Li, Ruoheng Jin, Zhijie Ren, Yao Qin, Chang Yu, Yongfeng Cai, Runhang Shu, Shun He, Jianhong Li, Adam C. N. Wong, Hu Wan