TY - JOUR

T1 - Genome mapping coupled with CRISPR gene editing reveals a P450 gene confers avermectin resistance in the beet armyworm

AU - Zuo, Yayun

AU - Shi, Yu

AU - Zhang, Feng

AU - Guan, Fang

AU - Zhang, Jianpeng

AU - Feyereisen, Rene

AU - Fabrick, Jeffrey A.

AU - Yang, Yihua

AU - Wu, Yidong

PY - 2021

Y1 - 2021

N2 - The evo of insecticide resistance represents a global constraint to agricultural production. Because of the extreme genetic diversity found in insects and the large numbers of genes involved in insecticide detoxification, better tools are needed to quickly identify and validate the involvement of putative resistance genes for improved monitoring, management, and countering of field-evolved insecticide resistance. The avermectins, emamectin benzoate (EB) and abamectin are relatively new pesticides with reduced environmental risk that target a wide number of insect pests, including the beet armyworm, Spodoptera exigua, an important global pest of many crops. Unfortunately, field resistance to avermectins recently evolved in the beet armyworm, threatening the sustainable use of this class of insecticides. Here, we report a high-quality chromosome-level assembly of the beet armyworm genome and use bulked segregant analysis (BSA) to identify the locus of avermectin resistance, which mapped on 15-16 Mbp of chromosome 17. Knockout of the CYP9A186 gene that maps within this region by CRISPR/Cas9 gene editing fully restored EB susceptibility, implicating this gene in avermectin resistance. Heterologous expression and in vitro functional assays further confirm that a natural substitution (F116V) found in the substrate recognition site 1 (SRS1) of the CYP9A186 protein results in enhanced metabolism of EB and abamectin. Hence, the combined approach of coupling gene editing with BSA allows for the rapid identification of metabolic resistance genes responsible for insecticide resistance, which is critical for effective monitoring and adaptive management of insecticide resistance.Author summary Insecticide resistance is a global constraint to agricultural production, and rapid identification of resistance genes is critical for better monitoring and management of resistant insect pests. Identification of metabolic resistance genes has always been a challenging task due to the high diversity of insect detoxification enzyme genes. Here, we report a high-quality chromosome-level assembly of the beet armyworm genome and use bulked segregant analysis (BSA) to identify the locus of avermectin resistance, which mapped on 15-16 Mbp of chromosome 17. Knockout of the CYP9A186 gene that maps within this region by CRISPR/Cas9 gene editing fully restored avermectin susceptibility. Heterologous expression and in vitro functional assays further confirm that a natural substitution (F116V) found in the substrate recognition site 1 (SRS1) of the CYP9A186 protein results in enhanced metabolism of avermectin. Hence, the combined approach of coupling gene editing with BSA allows for the rapid identification of metabolic resistance genes responsible for insecticide resistance, which is critical for field monitoring of such mutations, for making improved decisions on appropriate use of effective chemistries, as well for improvements in the design of future compounds that target S. exigua.

AB - The evo of insecticide resistance represents a global constraint to agricultural production. Because of the extreme genetic diversity found in insects and the large numbers of genes involved in insecticide detoxification, better tools are needed to quickly identify and validate the involvement of putative resistance genes for improved monitoring, management, and countering of field-evolved insecticide resistance. The avermectins, emamectin benzoate (EB) and abamectin are relatively new pesticides with reduced environmental risk that target a wide number of insect pests, including the beet armyworm, Spodoptera exigua, an important global pest of many crops. Unfortunately, field resistance to avermectins recently evolved in the beet armyworm, threatening the sustainable use of this class of insecticides. Here, we report a high-quality chromosome-level assembly of the beet armyworm genome and use bulked segregant analysis (BSA) to identify the locus of avermectin resistance, which mapped on 15-16 Mbp of chromosome 17. Knockout of the CYP9A186 gene that maps within this region by CRISPR/Cas9 gene editing fully restored EB susceptibility, implicating this gene in avermectin resistance. Heterologous expression and in vitro functional assays further confirm that a natural substitution (F116V) found in the substrate recognition site 1 (SRS1) of the CYP9A186 protein results in enhanced metabolism of EB and abamectin. Hence, the combined approach of coupling gene editing with BSA allows for the rapid identification of metabolic resistance genes responsible for insecticide resistance, which is critical for effective monitoring and adaptive management of insecticide resistance.Author summary Insecticide resistance is a global constraint to agricultural production, and rapid identification of resistance genes is critical for better monitoring and management of resistant insect pests. Identification of metabolic resistance genes has always been a challenging task due to the high diversity of insect detoxification enzyme genes. Here, we report a high-quality chromosome-level assembly of the beet armyworm genome and use bulked segregant analysis (BSA) to identify the locus of avermectin resistance, which mapped on 15-16 Mbp of chromosome 17. Knockout of the CYP9A186 gene that maps within this region by CRISPR/Cas9 gene editing fully restored avermectin susceptibility. Heterologous expression and in vitro functional assays further confirm that a natural substitution (F116V) found in the substrate recognition site 1 (SRS1) of the CYP9A186 protein results in enhanced metabolism of avermectin. Hence, the combined approach of coupling gene editing with BSA allows for the rapid identification of metabolic resistance genes responsible for insecticide resistance, which is critical for field monitoring of such mutations, for making improved decisions on appropriate use of effective chemistries, as well for improvements in the design of future compounds that target S. exigua.

KW - GATED CHLORIDE CHANNEL

KW - EXIGUA LEPIDOPTERA-NOCTUIDAE

KW - 2-SPOTTED SPIDER-MITE

KW - INSECTICIDE RESISTANCE

KW - ABAMECTIN RESISTANCE

KW - POINT MUTATION

KW - BIOCHEMICAL-MECHANISMS

KW - PLUTELLA-XYLOSTELLA

KW - CYTOCHROME P450S

KW - CROSS-RESISTANCE

U2 - 10.1371/journal.pgen.1009680

DO - 10.1371/journal.pgen.1009680

M3 - Journal article

C2 - 34252082

VL - 17

JO - P L o S Genetics

JF - P L o S Genetics

SN - 1553-7390

IS - 7

M1 - 1009680

ER -