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1.
PLoS Biol ; 22(7): e3002704, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38954724

ABSTRACT

The vegetative insecticidal protein Vip3Aa from Bacillus thuringiensis (Bt) has been produced by transgenic crops to counter pest resistance to the widely used crystalline (Cry) insecticidal proteins from Bt. To proactively manage pest resistance, there is an urgent need to better understand the genetic basis of resistance to Vip3Aa, which has been largely unknown. We discovered that retrotransposon-mediated alternative splicing of a midgut-specific chitin synthase gene was associated with 5,560-fold resistance to Vip3Aa in a laboratory-selected strain of the fall armyworm, a globally important crop pest. The same mutation in this gene was also detected in a field population. Knockout of this gene via CRISPR/Cas9 caused high levels of resistance to Vip3Aa in fall armyworm and 2 other lepidopteran pests. The insights provided by these results could help to advance monitoring and management of pest resistance to Vip3Aa.


Subject(s)
Bacillus thuringiensis , Bacterial Proteins , Chitin Synthase , Insecticide Resistance , Retroelements , Animals , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Chitin Synthase/genetics , Chitin Synthase/metabolism , Retroelements/genetics , Bacillus thuringiensis/genetics , Insecticide Resistance/genetics , CRISPR-Cas Systems , Alternative Splicing/genetics , Alternative Splicing/drug effects , Spodoptera/drug effects , Plants, Genetically Modified , Moths/drug effects , Moths/genetics
2.
Adv Sci (Weinh) ; : e2305353, 2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38965806

ABSTRACT

A fundamental understanding of the underlying mechanisms involved in biological invasions is crucial to developing effective risk assessment and control measures against invasive species. The fall armyworm (FAW), Spodoptera frugiperda, is a highly invasive pest that has rapidly spread from its native Americas into much of the Eastern Hemisphere, with a highly homogeneous nuclear genetic background. However, the exact mechanism behind its rapid introduction and propagation remains unclear. Here, a systematic investigation is conducted into the population dynamics of FAW in China from 2019 to 2021 and found that FAW individuals carrying "rice" mitochondria (FAW-mR) are more prevalent (>98%) than that with "corn" mitochondria (FAW-mC) at the initial stage of the invasion and in newly-occupied non-overwintering areas. Further fitness experiments show that the two hybrid-strains of FAW exhibit different adaptions in the new environment in China, and this may have been facilitated by amino acid changes in mitochondrial-encoded proteins. FAW-mR used increases energy metabolism, faster wing-beat frequencies, and lower wing loadings to drive greater flight performance and subsequent rapid colonization of new habitats. In contrast, FAW-mC individuals adapt with more relaxed mitochondria and shuttle energetics into maternal investment, observed as faster development rate and higher fecundity. The presence of two different mitochondria types within FAW has the potential to significantly expand the range of damage and enhance competitive advantage. Overall, the study describes a novel invasion mechanism displayed by the FAW population that facilitates its expansion and establishment in new environments.

3.
Pest Manag Sci ; 2024 Jul 19.
Article in English | MEDLINE | ID: mdl-39030881

ABSTRACT

BACKGROUND: Vegetative insecticidal proteins (Vips) are widely used in pest management, but Vip tolerance poses a significant threat. DNA methylation plays important roles in regulating the response of biological organisms to environmental stress, and it may also regulate fall armyworm (FAW, Spodoptera frugiperda) Vip3Aa tolerance. RESULTS: In this study, a DNA methylation map was developed for FAW, and its function in regulating FAW Vip3Aa tolerance was explored. The FAW genome-wide DNA methylation map showed that exons were preferred regions for DNA methylation and housekeeping genes were highly methylated. FAW was screened using Vip3Aa for ten generations, and bioassays indicated that Vip3Aa tolerance increased trans-generationally. A comparison of DNA methylation maps between Vip3Aa-tolerant and -susceptible strains showed that gene body methylation was positively correlated with gene expression level. FAW exhibits significant variation in DNA methylation among individuals, and Vip3Aa screening induces epigenetic variation based on DNA methylation. Moreover, the study demonstrated that a reduction in methylation density within the gene body of a 3'5'-cyclic nucleotide phosphodiesterase gene resulted in decreased expression and increased tolerance of FAW to Vip3Aa, which was validated through RNA interference experiments. CONCLUSION: The DNA methylation map and mechanism of Vip3Aa tolerance improve our understanding of DNA methylation and its function in Lepidoptera and provide a new perspective for developing pest management strategies. © 2024 Society of Chemical Industry.

4.
Sci Data ; 11(1): 338, 2024 Apr 05.
Article in English | MEDLINE | ID: mdl-38580759

ABSTRACT

Athetis lepigone is an emerging highly polyphagous insect pest reported to cause crop damage in several European and Asian countries. However, our understanding of its genetic adaptation mechanisms has been limited due to lack of high-quality genetic resources. In this study, we present a chromosomal-level genome of A. lepigone, representing the first species in the genus of Athetis. We employed PacBio long-read sequencing and Hi-C technologies to generate 612.49 Mb genome assembly which contains 42.43% repeat sequences with a scaffold N50 of 20.9 Mb. The contigs were successfully clustered into 31 chromosomal-size scaffolds with 37% GC content. BUSCO assessment revealed a genome completeness of 97.4% with 96.3 identified as core Arthropoda single copy orthologs. Among the 17,322 genes that were predicted, 15,965 genes were functionally annotated, representing a coverage of 92.17%. Furthermore, we revealed 106 P450, 37 GST, 27 UGT, and 74 COE gene families in the genome of A. lepigone. This genome provides a significant and invaluable genomic resource for further research across the entire genus of Athetis.


Subject(s)
Genome, Insect , Moths , Animals , Base Sequence , Genomics , Moths/genetics , Phylogeny , Chromosomes, Insect
5.
Nat Commun ; 15(1): 2559, 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38519521

ABSTRACT

Proteins containing a ubiquitin regulatory X (UBX) domain are cofactors of Cell Division Cycle 48 (CDC48) and function in protein quality control. However, whether and how UBX-containing proteins participate in host-microbe interactions remain unclear. Here we show that MoNLE1, an effector from the fungal pathogen Magnaporthe oryzae, is a core virulence factor that suppresses rice immunity by specifically interfering with OsPUX8B.2. The UBX domain of OsPUX8B.2 is required for its binding to OsATG8 and OsCDC48-6 and controls its 26 S proteasome-dependent stability. OsPUX8B.2 and OsCDC48-6 positively regulate plant immunity against blast fungus, while the high-temperature tolerance heat-shock protein OsBHT, a putative cytoplasmic substrate of OsPUX8B.2-OsCDC48-6, negatively regulates defense against blast infection. MoNLE1 promotes the nuclear migration and degradation of OsPUX8B.2 and disturbs its association with OsBHT. Given the high conservation of MoNLE1 among fungal isolates, plants with broad and durable blast resistance might be generated by engineering intracellular proteins resistant to MoNLE1.


Subject(s)
Magnaporthe , Oryza , Host-Pathogen Interactions , Plant Immunity/genetics , Biological Transport , Plants, Genetically Modified/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Oryza/metabolism , Plant Diseases/microbiology , Fungal Proteins/genetics , Fungal Proteins/metabolism
6.
Insect Sci ; 2024 Feb 27.
Article in English | MEDLINE | ID: mdl-38414321

ABSTRACT

The fall armyworm (FAW), Spodoptera frugiperda, has colonized and caused consistent damage in the Eastern hemisphere. The identification of various FAW strains is essential for developing precise prevention and control measures. The triosephosphate isomerase (Tpi) gene is recognized as an effective marker closely linked to FAW subpopulations. However, most current studies primarily focus on the comparison of variations in specific gene sites of this gene. In this study, we conducted full-length sequencing of the Tpi genes from 5 representative FAW groups. Our findings revealed that the Tpi genes varied in length from 1220 to 1420 bp, with the primary variation occurring within 4 introns. Notably, the exon lengths remained consistent, at 747 bp, with 37 observed base variations; however, no amino acid variations were detected. Through sequence alignment, we identified 8 stable variation sites that can be used to distinguish FAW strains in the Eastern hemisphere. Additionally, we performed strain identification on 1569 FAW samples collected from 19 provinces in China between 2020 and 2021. The extensive analysis indicated the absence of the rice strain in the samples. Instead, we only detected the presence of the corn strain and the Zambia strain, with the Zambia strain being distributed in a very low proportion (3.44%). Furthermore, the corn strain could be further categorized into 2 subgroups. This comprehensive study provides a valuable reference for enhancing our understanding of FAW population differentiation and for improving monitoring and early warning efforts.

7.
BMC Biol ; 22(1): 42, 2024 Feb 20.
Article in English | MEDLINE | ID: mdl-38378556

ABSTRACT

BACKGROUND: The adaptive mechanisms of agricultural pests are the key to understanding the evolution of the pests and to developing new control strategies. However, there are few studies on the genetic basis of adaptations of agricultural pests. The turnip moth, Agrotis segetum (Lepidoptera: Noctuidae) is an important underground pest that affects a wide range of host plants and has a strong capacity to adapt to new environments. It is thus a good model for studying the adaptive evolution of pest species. RESULTS: We assembled a high-quality reference genome of A. segetum using PacBio reads. Then, we constructed a variation map of A. segetum by resequencing 98 individuals collected from six natural populations in China. The analysis of the population structure showed that all individuals were divided into four well-differentiated populations, corresponding to their geographical distribution. Selective sweep analysis and environmental association studies showed that candidate genes associated with local adaptation were functionally correlated with detoxification metabolism and glucose metabolism. CONCLUSIONS: Our study of A. segetum has provided insights into the genetic mechanisms of local adaptation and evolution; it has also produced genetic resources for developing new pest management strategies.


Subject(s)
Metagenomics , Moths , Animals , Moths/genetics , China
8.
Insect Sci ; 2024 Jan 11.
Article in English | MEDLINE | ID: mdl-38204333

ABSTRACT

Understanding the genetic basis of adaptive evolution following habitat expansion can have important implications for pest management. The pink rice borer (PRB), Sesamia inferens (Walker), is a destructive pest of rice that was historically restricted to regions south of 34° N latitude in China. However, with changes in global climate and farming practices, the distribution of this moth has progressively expanded, encompassing most regions in North China. Here, 3 highly differentiated subpopulations were discovered using high-quality single-nucleotide polymorphism and structural variant datasets across China, corresponding to northern, southern China regions, and the Yunnan-Guizhou Plateau, with significant patterns of isolation by geographic and environmental distances. Our estimates of evolutionary history indicate asymmetric migration with varying population sizes across the 3 subpopulations. Selective sweep analyses estimated strong selection at insect cuticle glycine-rich cuticular protein genes which are associated with enhanced desiccation adaptability in the northern group, and at the histone-lysine-N-methyltransferase gene associated with range expansion and local adaptation in the Shandong population. Our findings have significant implications for the development of effective strategies to control this pest.

9.
Sci Data ; 11(1): 134, 2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38272921

ABSTRACT

The pink stem borer, Sesamia inferens (Walker), is a significant polyphagous pest historically restricted to regions south of N34° latitude. However, with changes in global climate and farming practices, the distribution of this moth has progressively exceeded its traditional limit of 34° N and encompassed most regions in North China. The genetic adaptations of S. inferens remain incompletely understood due to the lack of high-quality genome resources. Here, we sequenced the genome of S. inferens using PacBio and Hi-C technology, yielding a genome assembly of 865.04 Mb with contig N50 of 1.23 Mb. BUSCO analysis demonstrated this genome assembly has a high-level completeness of 96.1% gene coverage. In total, 459.72 Mb repeat sequences (53.14% of the assembled genome) and 20858 protein-coding genes were identified. We used the Hi-C technique to anchor 1135 contigs to 31 chromosomes, yielding a chromosome-level genome assembly with a scaffold N50 of 29.99 Mb. In conclusion, our high-quality genome assembly provided valuable resource that exploring the genetic characteristics of local adaptation and developing an efficient control strategy.


Subject(s)
Chromosomes , Genome, Insect , Moths , Animals , Base Sequence , Moths/genetics , Phylogeny , Repetitive Sequences, Nucleic Acid
10.
Sci Data ; 10(1): 805, 2023 11 16.
Article in English | MEDLINE | ID: mdl-37973925

ABSTRACT

The yellow peach moth, Conogethes punctiferalis, is a highly polyphagous pest widespread in eastern and southern Asia. It demonstrates a unique ability to adapt to rotten host fruits and displays resistance to pathogenic microorganisms, including fungi. However, the lack of available genomic resources presents a challenge in comprehensively understanding the evolution of its innate immune genes. Here, we report a high-quality chromosome-level reference genome for C. punctiferalis utilizing PacBio HiFi sequencing and Hi-C technology. The genome assembly was 494 Mb in length with a contig N50 of 3.25 Mb. We successfully anchored 1,226 contigs to 31 pseudochromosomes. Our BUSCO analysis further demonstrated a gene coverage completeness of 96.3% in the genome assembly. Approximately 43% repeat sequences and 21,663 protein-coding genes were identified. In addition, we resequenced 110 C. punctiferalis individuals from east China, achieving an average coverage of 18.4 × and identifying 5.8 million high-quality SNPs. This work provides a crucial resource for understanding the evolutionary mechanism of C. punctiferalis' innate immune system and will help in developing new antibacterial drugs.


Subject(s)
Genome, Insect , Moths , Animals , Chromosomes , Genomics , Moths/genetics , Phylogeny , Whole Genome Sequencing
11.
Proc Natl Acad Sci U S A ; 120(44): e2306932120, 2023 Oct 31.
Article in English | MEDLINE | ID: mdl-37874855

ABSTRACT

Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) have revolutionized control of some major pests. However, more than 25 cases of field-evolved practical resistance have reduced the efficacy of transgenic crops producing crystalline (Cry) Bt proteins, spurring adoption of alternatives including crops producing the Bt vegetative insecticidal protein Vip3Aa. Although practical resistance to Vip3Aa has not been reported yet, better understanding of the genetic basis of resistance to Vip3Aa is urgently needed to proactively monitor, delay, and counter pest resistance. This is especially important for fall armyworm (Spodoptera frugiperda), which has evolved practical resistance to Cry proteins and is one of the world's most damaging pests. Here, we report the identification of an association between downregulation of the transcription factor gene SfMyb and resistance to Vip3Aa in S. frugiperda. Results from a genome-wide association study, fine-scale mapping, and RNA-Seq identified this gene as a compelling candidate for contributing to the 206-fold resistance to Vip3Aa in a laboratory-selected strain. Experimental reduction of SfMyb expression in a susceptible strain using RNA interference (RNAi) or CRISPR/Cas9 gene editing decreased susceptibility to Vip3Aa, confirming that reduced expression of this gene can cause resistance to Vip3Aa. Relative to the wild-type promoter for SfMyb, the promoter in the resistant strain has deletions and lower activity. Data from yeast one-hybrid assays, genomics, RNA-Seq, RNAi, and proteomics identified genes that are strong candidates for mediating the effects of SfMyb on Vip3Aa resistance. The results reported here may facilitate progress in understanding and managing pest resistance to Vip3Aa.


Subject(s)
Bacillus thuringiensis , Insecticides , Animals , Bacillus thuringiensis/genetics , Spodoptera/genetics , Bacillus thuringiensis Toxins/metabolism , Down-Regulation , Transcription Factors/metabolism , Genome-Wide Association Study , Insecticides/pharmacology , Bacterial Proteins/genetics , Bacterial Proteins/pharmacology , Bacterial Proteins/metabolism , Crops, Agricultural/genetics , Endotoxins/genetics , Endotoxins/pharmacology , Endotoxins/metabolism , Hemolysin Proteins/metabolism , Insecticide Resistance/genetics , Larva/metabolism , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism
12.
Commun Biol ; 6(1): 1064, 2023 10 19.
Article in English | MEDLINE | ID: mdl-37857697

ABSTRACT

The rapid evolution of resistance in agricultural pest poses a serious threat to global food security. However, the mechanisms of resistance through metabolic regulation are largely unknown. Here, we found that a GST gene cluster was strongly selected in North China (NTC) population, and it was significantly genetically-linked to lambda-cyhalothrin resistance. Knockout of the GST cluster using CRISPR/Cas9 significantly increased the sensitivity of the knockout strain to lambda-cyhalothrin. Haplotype analysis revealed no non-synonymous mutations or structural variations in the GST cluster, whereas GST_119 and GST_121 were significantly overexpressed in the NTC population. Silencing of GST_119 or co-silencing of GST_119 and GST_121 with RNAi significantly increased larval sensitivity to lambda-cyhalothrin. We also identified additional GATAe transcription factor binding sites in the promoter of NTC_GST_119. Transient expression of GATAe in Hi5 cells activated NTC_GST_119 and Xinjiang (XJ)_GST_119 transcription, but the transcriptional activity of NTC_GST_119 was significantly higher than that of XJ_GST_119. These results demonstrate that variations in the regulatory region result in complex expression changes in the GST cluster, which enhances lambda-cyhalothrin resistance in field-populations. This study deepens our knowledge of the evolutionary mechanism of pest adaptation under environmental stress and provides potential targets for monitoring pest resistance and integrated management.


Subject(s)
Insecticides , Moths , Pyrethrins , Animals , Insecticides/pharmacology , Insecticide Resistance/genetics , Moths/genetics , Pyrethrins/pharmacology
13.
Mitochondrial DNA B Resour ; 8(9): 963-966, 2023.
Article in English | MEDLINE | ID: mdl-37701525

ABSTRACT

Tethea albicostata is a widely distributed insect species in northern and central China. To date, few studies have been conducted on this species, with the exception of morphological taxonomy studies. Here, we report the complete mitochondrial genome of T. albicostata collected in China. The circular-mapping mitogenome is 15,308 bp in length, with an overall A + T content of 80.52%, encoding 2 ribosomal RNA genes, 22 transfer RNA genes, and 13 protein-coding genes. The gene arrangement and components of T. albicostata are identical to those of most other Lepidopteran insects. Phylogenetic analysis based on mitogenomes showed that T. albicostata is grouped with Drepana pallida, which belongs to the same family as Drepanidae. The family Drepanidae formed a separate branch from other families in the phylogenetic tree. This study determined the second mitochondrial genome of the Drepanidae species.

14.
Front Physiol ; 14: 1254765, 2023.
Article in English | MEDLINE | ID: mdl-37680771

ABSTRACT

Introduction: The development of insecticide resistance in Spodoptera frugiperda populations is a serious threat to the crop industry. Given the spread of invasive resistant populations, prospective monitoring should be accelerated, and the development of diagnostic tools for rapid and accurate assessments of insecticide resistance is essential. Methods: First, the discriminating dose and diagnostic time of the kit were determined by the glass vial method based on a susceptible strain. Then, pests that were collected from field populations were used to determine their susceptibility to seven insecticides by using the diagnostic kit. Finally, the accuracy of the kit was verified based on correlation analyses and the likelihood of insecticide control failure was assessed. Results: Here, we describe a diagnostic kit that enables the rapid detection of resistance to chlorpyrifos, bifenthrin, deltamethrin, lambda-cyhalothrin, phoxim, chlorantraniliprole and chlorfenapyr within 1-2 h in S. frugiperda at diagnostic doses of 0.98, 0.84, 0.38, 1.64, 0.0082, 1.75 and 0.65 µg/cm2, respectively. The linear equation between mortalities under diagnostic doses and actual resistance ratios measured by the diet-overlay bioassay was determined. The high correlation indicates that the insecticide resistance levels diagnosed by the kit were consistent with the results of the diet-overlay bioassay. Moreover, we found a significant negative correlation between diagnostic mortality and the likelihood of control failure for bifenthrin (r = -0.899, p = 0.001), deltamethrin (r = -0.737, p = 0.024) and lambda-cyhalothrin (r = -0.871, p = 0.002). Discussion: The insecticide resistance diagnostic kit for S. frugiperda is a user-friendly tool (portable, short detection time). Its excellent performance qualifies the kit as a reliable screening tool for identifying effective insecticides in sustainable resistance management.

15.
Mol Ecol ; 32(20): 5463-5478, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37638537

ABSTRACT

The major plant pest fall armyworm (FAW), Spodoptera frugiperda, is native to the Americas and has colonized Africa and Asia within the Eastern hemisphere since 2016, causing severe damage to multiple agricultural crop species. However, the genetic origin of these invasive populations requires more in-depth exploration. We analysed genetic variation across the genomes of 280 FAW individuals from both the Eastern hemisphere and the Americas. The global range-wide genetic structure of FAW shows that the FAW in America has experienced deep differentiation, largely consistent with the Z-chromosomal Tpi haplotypes commonly used to differentiate 'corn-strain' and 'rice-strain' populations. The invasive populations from Africa and Asia are different from the American ones and have a relatively homogeneous population structure, consistent with the common origin and recent spreading from Africa to Asia. Our analyses suggest that north- and central American 'corn-strain' FAW are the most likely sources of the invasion into the Eastern hemisphere. Furthermore, evidence based on genomic, transcriptomic and mitochondrial haplotype network analyses indicates an earlier, independent introduction of FAW into Africa, with subsequent migration into the recent invasive population.

16.
Pestic Biochem Physiol ; 194: 105516, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37532331

ABSTRACT

Helicoverpa armigera is a worldwide pest that has been efficiently controlled by transgenic plants expressing Bt Cry toxins. To exert toxicity, Cry toxins bind to different receptors located in larval midgut cells. Previously, we reported that GATA transcription factor GATAe activates the expression of multiple H. armigera Cry1Ac receptors in different insect cell lines. Here, the mechanism involved in GATAe regulation of HaABCC2 gene expression, a key receptor of Cry1Ac, was analyzed. HaGATAe gene silencing by RNAi in H. armigera larvae confirmed the activation role of HaGATAe on the expression of HaABCC2 in the midgut. The contribution of all potential GATAe-binding sites was analyzed by site-directed mutagenesis using Hi5 cells expressing a reporter gene under regulation of different modified HaABCC2 promoters. DNA pull-down assays revealed that GATAe bound to different predicted GATA-binding sites and mutations of the different GATAe-binding sites identified two binding sites responsible for the promoter activity. The binding site B9, which is located near the transcription initiator site, has a major contribution on HaABCC2 expression. Also, DNA pull-down assays revealed that all other members of GATA TF family in H. armigera, besides GATAe, HaGATAa, HaGATAb, HaGATAc and HaGATAd also bound to the HaABCC2 promoter and decreased the GATAe dependent promoter activity. Finally, the potential participation in the regulation of HaABCC2 promoter of several TFs other than GATA TFs expressed in the midgut cells was analyzed. HaHR3 inhibited the GATAe dependent activity of the HaABCC2 promoter, while two other midgut-related TFs, HaCDX and HaSox21, also bound to the HaABCC2 promoter region and increased the GATAe dependent promoter activity. All these data showed that GATAe induces HaABCC2 expression by binding to HaGATAe binding sites in the promoter region and that additional TFs participate in modulating the HaGATAe-driven expression of HaABCC2.


Subject(s)
Helicoverpa armigera , Insecticides , GATA Transcription Factors , Multidrug Resistance-Associated Protein 2/genetics , Animals , Insecticides/toxicity
17.
Innovation (Camb) ; 4(4): 100454, 2023 Jul 10.
Article in English | MEDLINE | ID: mdl-37388193

ABSTRACT

The cotton bollworm, Helicoverpa armigera, is set to become the most economically devastating crop pest in the world, threatening food security and biosafety as its range expands across the globe. Key to understanding the eco-evolutionary dynamics of H. armigera, and thus its management, is an understanding of population connectivity and the adaptations that allow the pest to establish in unique environments. We assembled a chromosome-scale reference genome and re-sequenced 503 individuals spanning the species range to delineate global patterns of connectivity, uncovering a previously cryptic population structure. Using a genome-wide association study (GWAS) and cell line expression of major effect loci, we show that adaptive changes in a temperature- and light-sensitive developmental pathway enable facultative diapause and that adaptation of trehalose synthesis and transport underlies cold tolerance in extreme environments. Incorporating extensive pesticide resistance monitoring, we also characterize a suite of novel pesticide and Bt resistance alleles under selection in East China. These findings offer avenues for more effective management strategies and provide insight into how insects adapt to variable climatic conditions and newly colonized environments.

18.
Int J Biol Macromol ; 244: 125392, 2023 Jul 31.
Article in English | MEDLINE | ID: mdl-37321433

ABSTRACT

The fall armyworm, Spodoptera frugiperda, is a devastating pest in its native range Western Hemisphere and has become a major invasive pest around the globe. Transgenic crops producing Bt toxins have been widely used to control S. frugiperda. However, the evolution of resistance threatens the sustainability of Bt crops. Field-evolved S. frugiperda resistance to Bt crops was observed in America, whereas, no case of field-resistance was reported in its newly invaded East Hemisphere. Here we investigated the molecular mechanism of a Cry1Ab-resistant LZ-R strain of S. frugiperda, which selected 27-generations using Cry1Ab after being collected in corn fields from China. Complementation tests between LZ-R strain and SfABCC2-KO strain, which have been knockout SfABCC2 gene and confer 174-fold resistance to Cry1Ab, showed a similar level of resistance in the F1-progeny as their parent stains, indicating that a common locus of SfABCC2 mutation in LZ-R stain. Sequencing of the full length of SfABCC2 cDNA from LZ-R strain, we characterize a novel mutation allele of SfABCC2. Cross-resistance results showed that Cry1Ab-resistance strain also confers >260-fold resistance to Cry1F, with no cross-resistance to Vip3A. These results provided evidence of a novel SfABCC2 mutation allele in the newly invaded East Hemisphere of S. frugiperda.


Subject(s)
Bacillus thuringiensis , Endotoxins , Animals , Endotoxins/genetics , Endotoxins/pharmacology , Spodoptera/genetics , Alleles , Bacterial Proteins/genetics , Hemolysin Proteins/genetics , Hemolysin Proteins/pharmacology , Plants, Genetically Modified/genetics , Zea mays/genetics , Crops, Agricultural/genetics , Bacillus thuringiensis/genetics , Larva
19.
Int J Biol Macromol ; 242(Pt 3): 124981, 2023 Jul 01.
Article in English | MEDLINE | ID: mdl-37236572

ABSTRACT

The fall armyworm, Spodoptera frugiperda (J. E. Smith), has become one of the most damaging pests worldwide since its invasion of Africa, Asia and Oceania from 2016, threatening plants in 76 families including important crops. Genetics-based methods have proved to be an efficient way to control pests, especially invasive species, but many difficulties must be overcome to develop a transgenic insect strain, especially for a non-model species. Here we thus sought to identify a visible marker that would facilitate the distinction between genetically modified (GM) and non-transgenic insects, thereby simplifying mutation identification and facilitating the broader application of genome editing tools in non-model insects. Five genes (sfyellow-y, sfebony, sflaccase2, sfscarlet, and sfok) that are orthologs of well-studied genes in pigment metabolism were knocked out using the CRISPR/Cas9 system to identify candidate gene markers. Two genes, Sfebony and Sfscarlet, were identified responsible for body and compound eye coloration, respectively, in S. frugiperda, and could be potential visual markers for genetics-based pest management strategies.


Subject(s)
Moths , Humans , Animals , Spodoptera/genetics , Pigmentation/genetics , Crops, Agricultural , Zea mays , Larva
20.
Mol Biol Evol ; 40(5)2023 05 02.
Article in English | MEDLINE | ID: mdl-37155936

ABSTRACT

Understanding the genetic basis of pest adaptive evolution and the risk of adaptation in response to climate change is essential for the development of sustainable agricultural practices. However, the genetic basis of climatic adaptation for the Asian corn borer (ACB), Ostrinia furnacalis, the main pest of corn in Asia and Oceania, is poorly understood. Here, we revealed the genomic loci underlying the climatic adaptation and evolution in ACB by integrating population genomic and environmental factors. We assembled a 471-Mb chromosome-scale reference genome of ACB and resequenced 423 individuals covering 27 representative geographic areas. We inferred that the ACB effective population size changes tracked with the global temperature and followed by a recent decline. Based on an integrated analysis of whole-genome selection scans and genome-wide genotype-environment association studies, we revealed the genetic basis of ACB adaption to diverse climates. For diapause traits, we identified a major effect association locus containing a circadian clock gene (period) by analyzing a diapause-segregating population. Moreover, our predictions indicated that the northern populations were more ecologically resilient to climate change than the southern populations. Together, our results revealed the genomic basis for ACB environmental adaptation and provided potential candidate genes for future evolutionary studies and genetic adaptation to climate change, intending to maintain the efficacy and sustainability of novel control techniques.


Subject(s)
Moths , Zea mays , Animals , Zea mays/genetics , Metagenomics , Biodiversity , Temperature , Moths/genetics , Asia
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