The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Lili Zhu - One of the best experts on this subject based on the ideXlab platform.
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Genomics of interaction between the Brown Planthopper and rice.
Current opinion in insect science, 2017Co-Authors: Shengli Jing, Yan Zhao, Rongzhi Chen, Lili ZhuAbstract:Rice (Oryza sativa L.) and the Brown Planthopper (Nilaparvata lugens (Stål)) form a model system for dissection of the mechanism of interaction between insect pest and crop. In this review, we focus on the genomics of BPH-rice interaction. On the side of rice, a number of BPH-resistance genes have been identified genetically. Thirteen of these genes have been cloned which shed a light on the molecular basis of the interaction. On the aspect of BPH, a lot of salivary proteins have been identified using transcriptome and proteome techniques. The genetic loci of virulence were mapped in BPH genome based on the linkage map. The understanding of interaction between BPH and rice will provide novel insights into efficient control of this pest.
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Genome-wide mapping of virulence in Brown Planthopper identifies loci that break down host plant resistance.
PloS one, 2014Co-Authors: Shengli Jing, Lei Zhang, Bingfang Liu, Yan Zhao, Xi Zhou, Rui Qin, Lili ZhuAbstract:Insects and plants have coexisted for over 350 million years and their interactions have affected ecosystems and agricultural practices worldwide. Variation in herbivorous insects' virulence to circumvent host resistance has been extensively documented. However, despite decades of investigation, the genetic foundations of virulence are currently unknown. The Brown Planthopper (Nilaparvata lugens) is the most destructive rice (Oryza sativa) pest in the world. The identification of the resistance gene Bph1 and its introduction in commercial rice varieties prompted the emergence of a new virulent Brown Planthopper biotype that was able to break the resistance conferred by Bph1. In this study, we aimed to construct a high density linkage map for the Brown Planthopper and identify the loci responsible for its virulence in order to determine their genetic architecture. Based on genotyping data for hundreds of molecular markers in three mapping populations, we constructed the most comprehensive linkage map available for this species, covering 96.6% of its genome. Fifteen chromosomes were anchored with 124 gene-specific markers. Using genome-wide scanning and interval mapping, the Qhp7 locus that governs preference for Bph1 plants was mapped to a 0.1 cM region of chromosome 7. In addition, two major QTLs that govern the rate of insect growth on resistant rice plants were identified on chromosomes 5 (Qgr5) and 14 (Qgr14). This is the first study to successfully locate virulence in the genome of this important agricultural insect by marker-based genetic mapping. Our results show that the virulence which overcomes the resistance conferred by Bph1 is controlled by a few major genes and that the components of virulence originate from independent genetic characters. The isolation of these loci will enable the elucidation of the molecular mechanisms underpinning the rice-Brown Planthopper interaction and facilitate the development of durable approaches for controlling this most destructive agricultural insect.
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Development and use of EST-SSR markers for assessing genetic diversity in the Brown Planthopper ( Nilaparvata lugens Stål)
Bulletin of entomological research, 2011Co-Authors: S. Jing, B. Liu, L. Peng, Xinxin Peng, Lili ZhuAbstract:To assess genetic diversity in populations of the Brown Planthopper ( Nilaparvata lugens Stal) (Homoptera: Delphacidae), we have developed and applied microsatellite, or simple sequence repeat (SSR), markers from expressed sequence tags (ESTs). We found that the Brown Planthopper clusters of ESTs were rich in SSRs with unique frequencies and distributions of SSR motifs. Three hundred and fifty-one EST-SSR markers were developed and yielded clear bands from samples of four Brown Planthopper populations. High cross-species transferability of these markers was detected in the closely related Planthopper N. muiri . The newly developed EST-SSR markers provided sufficient resolution to distinguish within and among biotypes. Analyses based on SSR data revealed host resistance-based genetic differentiation among different Brown Planthopper populations; the genetic diversity of populations feeding on susceptible rice varieties was lower than that of populations feeding on resistant rice varieties. This is the first large-scale development of Brown Planthopper SSR markers, which will be useful for future molecular genetics and genomics studies of this serious agricultural pest.
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Bacterial symbionts of the Brown Planthopper, Nilaparvata lugens (Homoptera: Delphacidae).
Applied and environmental microbiology, 2010Co-Authors: Ming Tang, Shengli Jing, Lili ZhuAbstract:The Brown Planthopper (Nilaparvata lugens Stal), the most destructive pest of rice, has been identified, including biotypes with high virulence towards previously resistant rice varieties. There have also been many reports of a yeast-like symbiont of N. lugens, but little is known about the bacterial microbes. In this study, we examined the bacterial microbes in N. lugens and identified a total of 18 operational taxonomic units (OTUs) representing four phyla (Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes) by sequencing and analyzing 16S rRNA gene libraries obtained from three populations of N. lugens, which were maintained on the rice varieties TN1, Mudgo, and ASD7. Several of the OTUs were similar to previously reported secondary symbionts of other insects, including an endosymbiont of the psyllid Glycapsis brimblecombei, an Asaia sp. found in the mosquito Anopheles stephensi, and Wolbachia, found in the mite Metaseiulus occidentalis. However, the species and numbers of the detected OTUs differed substantially among the N. lugens populations. Further, in situ hybridization analysis using digoxigenin-labeled probes indicated that OTU 1 was located in hypogastrium tissues near the ovipositor and ovary in biotype 1 insects, while OTU 2 was located in the front of the ovipositor sheath in biotype 2 insects. In addition, masses of bacterium-like organisms were observed in the tubes of salivary sheaths in rice plant tissues that the insects had fed upon. The results provide indications of the diversity of the bacterial microbes harbored by the Brown Planthopper and of possible associations between specific bacterial microbes and biotypes of N. lugens.
Zewen Liu - One of the best experts on this subject based on the ideXlab platform.
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neonicotinoid resistance in rice Brown Planthopper nilaparvata lugens
Pest Management Science, 2008Co-Authors: Kevin Gorman, Zewen Liu, I Denholm, Kaiuwe Dr Bruggen, Ralf NauenAbstract:BACKGROUND: Rice Brown Planthopper, Nilaparvata lugens StÅl, is a primary insect pest of cultivated rice, and effective control is essential for economical crop production. Resistance to neonicotinoid insecticides, in particular imidacloprid, has been reported as an increasing constraint in recent years. In order to investigate the extent of resistance, 24 samples of N. lugens were collected from China, India, Indonesia, Malaysia, Thailand and Vietnam during 2005 and 2006. Their responses to two diagnostic doses of imidacloprid (corresponding approximately to the LC 95 and 5 x LC 95 of a susceptible strain) were examined. RESULTS: Ten of the 12 samples collected during 2005 were found to be susceptible to imidacloprid, but two late-season samples from India showed reduced mortality at both diagnostic doses. All 13 strains collected in 2006 showed reduced mortality at both doses when compared with the susceptible strain. Dose-response lines showed resistance in one of the most resistant field strains to be approximately 100-fold compared with the susceptible standard. CONCLUSION: The data demonstrate the development and spread of neonicotinoid resistance in N. lugens in Asia and support reports of reduced field efficacy of imidacloprid.
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fitness costs of laboratory selected imidacloprid resistance in the Brown Planthopper nilaparvata lugens stal
Pest Management Science, 2006Co-Authors: Zewen Liu, Zhaojun HanAbstract:Imidacloprid has been used as a key insecticide to control the Brown Planthopper, Nilaparvata lugens Stal, for several years, but no obvious resistance has been identified in field populations as yet. To evaluate the risk, a field population was collected and selected with imidacloprid in the laboratory. After 37-generation selection a strain with 250-fold resistance had been successfully achieved. Fitness analysis by constructing life tables demonstrated that resistant hoppers had obvious disadvantages in their reproduction. The fitness of highly resistant hoppers had decreased dramatically (0.169 and 0.104) to only one-fifth to one-tenth of that of the susceptible strain. Hence it was concluded that the Brown Planthopper had the potential to develop high resistance to imidacloprid but that the lower fitness of resistant hoppers could result in a quick recovery of sensitivity when the population did not come into contact with imidacloprid. This means that a reasonable resistance management programme with less imidacloprid use may efficiently delay or even stop resistance development.
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Fitness costs of laboratory‐selected imidacloprid resistance in the Brown Planthopper, Nilaparvata lugens Stål
Pest management science, 2006Co-Authors: Zewen Liu, Zhaojun HanAbstract:Imidacloprid has been used as a key insecticide to control the Brown Planthopper, Nilaparvata lugens Stal, for several years, but no obvious resistance has been identified in field populations as yet. To evaluate the risk, a field population was collected and selected with imidacloprid in the laboratory. After 37-generation selection a strain with 250-fold resistance had been successfully achieved. Fitness analysis by constructing life tables demonstrated that resistant hoppers had obvious disadvantages in their reproduction. The fitness of highly resistant hoppers had decreased dramatically (0.169 and 0.104) to only one-fifth to one-tenth of that of the susceptible strain. Hence it was concluded that the Brown Planthopper had the potential to develop high resistance to imidacloprid but that the lower fitness of resistant hoppers could result in a quick recovery of sensitivity when the population did not come into contact with imidacloprid. This means that a reasonable resistance management programme with less imidacloprid use may efficiently delay or even stop resistance development.
Zhaojun Han - One of the best experts on this subject based on the ideXlab platform.
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fitness costs of laboratory selected imidacloprid resistance in the Brown Planthopper nilaparvata lugens stal
Pest Management Science, 2006Co-Authors: Zewen Liu, Zhaojun HanAbstract:Imidacloprid has been used as a key insecticide to control the Brown Planthopper, Nilaparvata lugens Stal, for several years, but no obvious resistance has been identified in field populations as yet. To evaluate the risk, a field population was collected and selected with imidacloprid in the laboratory. After 37-generation selection a strain with 250-fold resistance had been successfully achieved. Fitness analysis by constructing life tables demonstrated that resistant hoppers had obvious disadvantages in their reproduction. The fitness of highly resistant hoppers had decreased dramatically (0.169 and 0.104) to only one-fifth to one-tenth of that of the susceptible strain. Hence it was concluded that the Brown Planthopper had the potential to develop high resistance to imidacloprid but that the lower fitness of resistant hoppers could result in a quick recovery of sensitivity when the population did not come into contact with imidacloprid. This means that a reasonable resistance management programme with less imidacloprid use may efficiently delay or even stop resistance development.
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Fitness costs of laboratory‐selected imidacloprid resistance in the Brown Planthopper, Nilaparvata lugens Stål
Pest management science, 2006Co-Authors: Zewen Liu, Zhaojun HanAbstract:Imidacloprid has been used as a key insecticide to control the Brown Planthopper, Nilaparvata lugens Stal, for several years, but no obvious resistance has been identified in field populations as yet. To evaluate the risk, a field population was collected and selected with imidacloprid in the laboratory. After 37-generation selection a strain with 250-fold resistance had been successfully achieved. Fitness analysis by constructing life tables demonstrated that resistant hoppers had obvious disadvantages in their reproduction. The fitness of highly resistant hoppers had decreased dramatically (0.169 and 0.104) to only one-fifth to one-tenth of that of the susceptible strain. Hence it was concluded that the Brown Planthopper had the potential to develop high resistance to imidacloprid but that the lower fitness of resistant hoppers could result in a quick recovery of sensitivity when the population did not come into contact with imidacloprid. This means that a reasonable resistance management programme with less imidacloprid use may efficiently delay or even stop resistance development.
Ralf Nauen - One of the best experts on this subject based on the ideXlab platform.
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neofunctionalization of duplicated p450 genes drives the evolution of insecticide resistance in the Brown Planthopper
Current Biology, 2018Co-Authors: Christoph T Zimmer, Ralf Nauen, William T Garrood, Kumar Saurabh Singh, Emma Randall, Bettina Lueke, Oliver Gutbrod, Svend Matthiesen, Maxie Kohler, T Emyr G DaviesAbstract:Summary Gene duplication is a major source of genetic variation that has been shown to underpin the evolution of a wide range of adaptive traits [1, 2]. For example, duplication or amplification of genes encoding detoxification enzymes has been shown to play an important role in the evolution of insecticide resistance [3–5]. In this context, gene duplication performs an adaptive function as a result of its effects on gene dosage and not as a source of functional novelty [3, 6–8]. Here, we show that duplication and neofunctionalization of a cytochrome P450, CYP6ER1, led to the evolution of insecticide resistance in the Brown Planthopper. Considerable genetic variation was observed in the coding sequence of CYP6ER1 in populations of Brown Planthopper collected from across Asia, but just two sequence variants are highly overexpressed in resistant strains and metabolize imidacloprid. Both variants are characterized by profound amino-acid alterations in substrate recognition sites, and the introduction of these mutations into a susceptible P450 sequence is sufficient to confer resistance. CYP6ER1 is duplicated in resistant strains with individuals carrying paralogs with and without the gain-of-function mutations. Despite numerical parity in the genome, the susceptible and mutant copies exhibit marked asymmetry in their expression with the resistant paralogs overexpressed. In the primary resistance-conferring CYP6ER1 variant, this results from an extended region of novel sequence upstream of the gene that provides enhanced expression. Our findings illustrate the versatility of gene duplication in providing opportunities for functional and regulatory innovation during the evolution of an adaptive trait.
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neonicotinoid resistance in rice Brown Planthopper nilaparvata lugens
Pest Management Science, 2008Co-Authors: Kevin Gorman, Zewen Liu, I Denholm, Kaiuwe Dr Bruggen, Ralf NauenAbstract:BACKGROUND: Rice Brown Planthopper, Nilaparvata lugens StÅl, is a primary insect pest of cultivated rice, and effective control is essential for economical crop production. Resistance to neonicotinoid insecticides, in particular imidacloprid, has been reported as an increasing constraint in recent years. In order to investigate the extent of resistance, 24 samples of N. lugens were collected from China, India, Indonesia, Malaysia, Thailand and Vietnam during 2005 and 2006. Their responses to two diagnostic doses of imidacloprid (corresponding approximately to the LC 95 and 5 x LC 95 of a susceptible strain) were examined. RESULTS: Ten of the 12 samples collected during 2005 were found to be susceptible to imidacloprid, but two late-season samples from India showed reduced mortality at both diagnostic doses. All 13 strains collected in 2006 showed reduced mortality at both doses when compared with the susceptible strain. Dose-response lines showed resistance in one of the most resistant field strains to be approximately 100-fold compared with the susceptible standard. CONCLUSION: The data demonstrate the development and spread of neonicotinoid resistance in N. lugens in Asia and support reports of reduced field efficacy of imidacloprid.
Shengli Jing - One of the best experts on this subject based on the ideXlab platform.
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Genomics of interaction between the Brown Planthopper and rice.
Current opinion in insect science, 2017Co-Authors: Shengli Jing, Yan Zhao, Rongzhi Chen, Lili ZhuAbstract:Rice (Oryza sativa L.) and the Brown Planthopper (Nilaparvata lugens (Stål)) form a model system for dissection of the mechanism of interaction between insect pest and crop. In this review, we focus on the genomics of BPH-rice interaction. On the side of rice, a number of BPH-resistance genes have been identified genetically. Thirteen of these genes have been cloned which shed a light on the molecular basis of the interaction. On the aspect of BPH, a lot of salivary proteins have been identified using transcriptome and proteome techniques. The genetic loci of virulence were mapped in BPH genome based on the linkage map. The understanding of interaction between BPH and rice will provide novel insights into efficient control of this pest.
-
Genome-wide mapping of virulence in Brown Planthopper identifies loci that break down host plant resistance.
PloS one, 2014Co-Authors: Shengli Jing, Lei Zhang, Bingfang Liu, Yan Zhao, Xi Zhou, Rui Qin, Lili ZhuAbstract:Insects and plants have coexisted for over 350 million years and their interactions have affected ecosystems and agricultural practices worldwide. Variation in herbivorous insects' virulence to circumvent host resistance has been extensively documented. However, despite decades of investigation, the genetic foundations of virulence are currently unknown. The Brown Planthopper (Nilaparvata lugens) is the most destructive rice (Oryza sativa) pest in the world. The identification of the resistance gene Bph1 and its introduction in commercial rice varieties prompted the emergence of a new virulent Brown Planthopper biotype that was able to break the resistance conferred by Bph1. In this study, we aimed to construct a high density linkage map for the Brown Planthopper and identify the loci responsible for its virulence in order to determine their genetic architecture. Based on genotyping data for hundreds of molecular markers in three mapping populations, we constructed the most comprehensive linkage map available for this species, covering 96.6% of its genome. Fifteen chromosomes were anchored with 124 gene-specific markers. Using genome-wide scanning and interval mapping, the Qhp7 locus that governs preference for Bph1 plants was mapped to a 0.1 cM region of chromosome 7. In addition, two major QTLs that govern the rate of insect growth on resistant rice plants were identified on chromosomes 5 (Qgr5) and 14 (Qgr14). This is the first study to successfully locate virulence in the genome of this important agricultural insect by marker-based genetic mapping. Our results show that the virulence which overcomes the resistance conferred by Bph1 is controlled by a few major genes and that the components of virulence originate from independent genetic characters. The isolation of these loci will enable the elucidation of the molecular mechanisms underpinning the rice-Brown Planthopper interaction and facilitate the development of durable approaches for controlling this most destructive agricultural insect.
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Bacterial symbionts of the Brown Planthopper, Nilaparvata lugens (Homoptera: Delphacidae).
Applied and environmental microbiology, 2010Co-Authors: Ming Tang, Shengli Jing, Lili ZhuAbstract:The Brown Planthopper (Nilaparvata lugens Stal), the most destructive pest of rice, has been identified, including biotypes with high virulence towards previously resistant rice varieties. There have also been many reports of a yeast-like symbiont of N. lugens, but little is known about the bacterial microbes. In this study, we examined the bacterial microbes in N. lugens and identified a total of 18 operational taxonomic units (OTUs) representing four phyla (Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes) by sequencing and analyzing 16S rRNA gene libraries obtained from three populations of N. lugens, which were maintained on the rice varieties TN1, Mudgo, and ASD7. Several of the OTUs were similar to previously reported secondary symbionts of other insects, including an endosymbiont of the psyllid Glycapsis brimblecombei, an Asaia sp. found in the mosquito Anopheles stephensi, and Wolbachia, found in the mite Metaseiulus occidentalis. However, the species and numbers of the detected OTUs differed substantially among the N. lugens populations. Further, in situ hybridization analysis using digoxigenin-labeled probes indicated that OTU 1 was located in hypogastrium tissues near the ovipositor and ovary in biotype 1 insects, while OTU 2 was located in the front of the ovipositor sheath in biotype 2 insects. In addition, masses of bacterium-like organisms were observed in the tubes of salivary sheaths in rice plant tissues that the insects had fed upon. The results provide indications of the diversity of the bacterial microbes harbored by the Brown Planthopper and of possible associations between specific bacterial microbes and biotypes of N. lugens.
