The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Natraj Krishnan - One of the best experts on this subject based on the ideXlab platform.
-
susceptibility to insecticides and activities of glutathione s transferase and esterase in populations of Lygus lineolaris hemiptera miridae in mississippi
Pest Management Science, 2016Co-Authors: Daniel Fleming, Natraj Krishnan, Angus L Catchot, Fred R. MusserAbstract:BACKGROUND Lygus lineolaris (Palisot de Beauvois) is a serious pest of cotton (Gossypium hirsutum L.) in Mississippi, particularly in the Delta region. This may be due to decreased insecticide susceptibility in that region. Research has revealed populations of L. lineolaris in the Delta region with high levels of insecticide resistance; however, comparisons with populations in the remainder of the state are limited. RESULTS Experiments were undertaken to compare the LC50 values and activities of detoxification enzymes of L. lineolaris populations. The results of these studies indicated that the LC50 values were not different between the Delta and Hills regions, but differences were significant between populations within and across regions. Results of the detoxifying enzyme activity assays revealed significantly higher esterase activity in the Delta region when compared with the Hills. Glutathione S-transferase activity was not different between regions, but differences within and across regions were significant. CONCLUSION The results indicated that glass-vial assays to determine and compare LC50 values may be less accurate than enzymatic assays for detecting insecticide susceptibility differences. Higher esterase activity is likely a contributing factor to the difficulties with managing L. lineolaris in the Mississippi Delta region. © 2015 Society of Chemical Industry.
-
insight into the salivary gland transcriptome of Lygus lineolaris palisot de beauvois
PLOS ONE, 2016Co-Authors: Kurt C. Showmaker, Andrea Bednářová, Chuan-yu Hsu, Daniel G. Peterson, Cathy R Gresham, Natraj KrishnanAbstract:The tarnished plant bug (TPB), Lygus lineolaris (Palisot de Beauvois) is a polyphagous, phytophagous insect that has emerged as a major pest of cotton, alfalfa, fruits, and vegetable crops in the eastern United States and Canada. Using its piercing-sucking mouthparts, TPB employs a “lacerate and flush” feeding strategy in which saliva injected into plant tissue degrades cell wall components and lyses cells whose contents are subsequently imbibed by the TPB. It is known that a major component of TPB saliva is the polygalacturonase enzymes that degrade the pectin in the cell walls. However, not much is known about the other components of the saliva of this important pest. In this study, we explored the salivary gland transcriptome of TPB using Illumina sequencing. After in silico conversion of RNA sequences into corresponding polypeptides, 25,767 putative proteins were discovered. Of these, 19,540 (78.83%) showed significant similarity to known proteins in the either the NCBI nr or Uniprot databases. Gene ontology (GO) terms were assigned to 7,512 proteins, and 791 proteins in the sialotranscriptome of TPB were found to collectively map to 107 Kyoto Encyclopedia of Genes and Genomes (KEGG) database pathways. A total of 3,653 Pfam domains were identified in 10,421 sialotranscriptome predicted proteins resulting in 12,814 Pfam annotations; some proteins had more than one Pfam domain. Functional annotation revealed a number of salivary gland proteins that potentially facilitate degradation of host plant tissues and mitigation of the host plant defense response. These transcripts/proteins and their potential roles in TPB establishment are described.
-
Scanning electron micrograph of excised salivary glands of the tarnished plant bug Lygus lineolaris.
2016Co-Authors: Kurt C. Showmaker, Andrea Bednářová, Cathy Gresham, Chuan-yu Hsu, Daniel G. Peterson, Natraj KrishnanAbstract:Scanning electron micrograph of excised salivary glands of the tarnished plant bug Lygus lineolaris.
-
Susceptibility to insecticides and activities of glutathione S‐transferase and esterase in populations of Lygus lineolaris (Hemiptera: Miridae) in Mississippi
Pest management science, 2015Co-Authors: Daniel Fleming, Natraj Krishnan, Angus L Catchot, Fred R. MusserAbstract:BACKGROUND Lygus lineolaris (Palisot de Beauvois) is a serious pest of cotton (Gossypium hirsutum L.) in Mississippi, particularly in the Delta region. This may be due to decreased insecticide susceptibility in that region. Research has revealed populations of L. lineolaris in the Delta region with high levels of insecticide resistance; however, comparisons with populations in the remainder of the state are limited. RESULTS Experiments were undertaken to compare the LC50 values and activities of detoxification enzymes of L. lineolaris populations. The results of these studies indicated that the LC50 values were not different between the Delta and Hills regions, but differences were significant between populations within and across regions. Results of the detoxifying enzyme activity assays revealed significantly higher esterase activity in the Delta region when compared with the Hills. Glutathione S-transferase activity was not different between regions, but differences within and across regions were significant. CONCLUSION The results indicated that glass-vial assays to determine and compare LC50 values may be less accurate than enzymatic assays for detecting insecticide susceptibility differences. Higher esterase activity is likely a contributing factor to the difficulties with managing L. lineolaris in the Mississippi Delta region. © 2015 Society of Chemical Industry.
Margaret L Allen - One of the best experts on this subject based on the ideXlab platform.
-
Genetics of a sex-linked recessive red eye color mutant of the tarnished plant bug, Lygus lineolaris
Open Journal of Animal Sciences, 2013Co-Authors: Margaret L AllenAbstract:An inbred colony of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Miridae: Hemiptera), was observed to contain specimens with abnormal traits including red eyes, deformed antennae, and deformed legs. These specimens were isolated and back crossed to create stable phenotypic strains. The only successful strain established was a red eyed strain named Cardinal. The trait was more prevalent and stable in males, suggesting that it could be sex linked. To test the hypothesis that the trait was based on a recessive sex linked allele, classical genetic crosses were performed. The hypothesis was confirmed, and the eye color phenotype was measured and characterized using color analysis software. The trait is similar to other red eyed phenotypes described in this species, but is clearly based on a different mutation since it is sex linked rather than autosomal. The results of crossing experiments also suggest that inbreeding in this species results in substantial fitness cost to laboratory insects.
-
saliva of Lygus lineolaris digests double stranded ribonucleic acids
Journal of Insect Physiology, 2012Co-Authors: Margaret L Allen, William B WalkerAbstract:The prospects for development of highly specific pesticides based on double stranded ribonucleic acid have been a recent focus of scientific research. Creative applications have been proposed and demonstrated. However, not all insects are sensitive to double stranded RNA (dsRNA) gene knockdown effects; applications in the order Lepidoptera, for example, have met with varied success. Gene knockdown has been demonstrated in several species in the order Hemiptera. In our laboratory, knockdown experiments relied on microinjection of dsRNA into the hemocoel of the tarnished plant bug, Lygus lineolaris. Subsequent experiments delivering dsRNA to insects by feeding were repeatedly unsuccessful in demonstrating knockdown, and a hypothesis was formulated that the dsRNA was digested and degraded by the insect prior to contact with the insect cells. Exposure of dsRNA to insect saliva, insect salivary glands, and insect hemolymph was compared with commercial RNAase III. The saliva of L. lineolaris was found to rapidly digest double stranded RNA. RNAase inhibitor did not affect the activity but heat treatment slowed enzymatic activity.
-
rna interference mediated knockdown of iap in Lygus lineolaris induces mortality in adult and pre adult life stages
Entomologia Experimentalis Et Applicata, 2011Co-Authors: William B Walker, Margaret L AllenAbstract:In recent years, RNA interference (RNAi) has been validated as a viable approach for functional genetic studies in non-model organisms. In this report we demonstrate the efficacy of RNAi in the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Miridae: Hemiptera). A L. lineolaris inhibitor of apoptosis gene (LlIAP) has been identified and cloned. The translated sequence encodes a 381 amino acid protein similar to other insect IAPs and contains two conserved baculovirus inhibitor of apoptosis protein repeat (BIR) domains. Microinjection of double stranded RNA (dsRNA) corresponding to two disparate portions of the gene resulted in decreased LlIAP mRNA quantities relative to controls. Both nymphs and adult specimens injected with IAP dsRNA exhibited significantly reduced lifespan compared with those injected with non-insect dsRNA (eGFP). Thus, RNAi-mediated knockdown of LlIAP expression has been correlated with a lethal phenotype in adults and nymphs.
-
expression and rna interference of salivary polygalacturonase genes in the tarnished plant bug Lygus lineolaris
Journal of Insect Science, 2010Co-Authors: William B Walker, Margaret L AllenAbstract:Three genes encoding polygalacturonase (PG) have been identified in Lygus lineolaris (Palisot de Beauvois) (Miridae: Hemiptera). Earlier studies showed that the three PG gene transcripts are exclusively expressed in the feeding stages of L. lineolaris. In this report, it is shown that all three transcripts are specifically expressed in salivary glands indicating that PGs are salivary enzymes. Transcriptional profiles of the three PGs were evaluated with respect to diet, comparing live cotton plant material to artificial diet. PG2 transcript levels were consistently lower in cotton-fed insects than those reared on artificial diet. RNA interference was used to knock down expression of PG1 mRNA in adult salivary glands providing the first demonstration of the use of this method in the non-model insect, L. lineolaris.
-
molecular cloning and expression of three polygalacturonase cdnas from the tarnished plant bug Lygus lineolaris
Journal of Insect Science, 2008Co-Authors: Margaret L Allen, Jeffrey A MertensAbstract:Three unique cDNAs encoding putative polygalacturonase enzymes were isolated from the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae). The three nucleotide sequences were dissimilar to one another, but the deduced amino acid sequences were similar to each other and to other polygalacturonases from insects, fungi, plants, and bacteria. Four conserved segments characteristic of polygalacturonases were present, but with some notable semiconservative substitutions. Two of four expected disulfide bridge—forming cysteine pairs were present. All three inferred protein translations included predicted signal sequences of 17 to 20 amino acids. Amplification of genomic DNA identified an intron in one of the genes, Llpg1, in the 5′ untranslated region. Semiquantitative RT-PCR revealed expression in all stages of the insect except the eggs. Expression in adults, male and female, was highly variable, indicating a family of highly inducible and diverse enzymes adapted to the generalist polyphagous nature of this important pest.
William B Walker - One of the best experts on this subject based on the ideXlab platform.
-
saliva of Lygus lineolaris digests double stranded ribonucleic acids
Journal of Insect Physiology, 2012Co-Authors: Margaret L Allen, William B WalkerAbstract:The prospects for development of highly specific pesticides based on double stranded ribonucleic acid have been a recent focus of scientific research. Creative applications have been proposed and demonstrated. However, not all insects are sensitive to double stranded RNA (dsRNA) gene knockdown effects; applications in the order Lepidoptera, for example, have met with varied success. Gene knockdown has been demonstrated in several species in the order Hemiptera. In our laboratory, knockdown experiments relied on microinjection of dsRNA into the hemocoel of the tarnished plant bug, Lygus lineolaris. Subsequent experiments delivering dsRNA to insects by feeding were repeatedly unsuccessful in demonstrating knockdown, and a hypothesis was formulated that the dsRNA was digested and degraded by the insect prior to contact with the insect cells. Exposure of dsRNA to insect saliva, insect salivary glands, and insect hemolymph was compared with commercial RNAase III. The saliva of L. lineolaris was found to rapidly digest double stranded RNA. RNAase inhibitor did not affect the activity but heat treatment slowed enzymatic activity.
-
rna interference mediated knockdown of iap in Lygus lineolaris induces mortality in adult and pre adult life stages
Entomologia Experimentalis Et Applicata, 2011Co-Authors: William B Walker, Margaret L AllenAbstract:In recent years, RNA interference (RNAi) has been validated as a viable approach for functional genetic studies in non-model organisms. In this report we demonstrate the efficacy of RNAi in the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Miridae: Hemiptera). A L. lineolaris inhibitor of apoptosis gene (LlIAP) has been identified and cloned. The translated sequence encodes a 381 amino acid protein similar to other insect IAPs and contains two conserved baculovirus inhibitor of apoptosis protein repeat (BIR) domains. Microinjection of double stranded RNA (dsRNA) corresponding to two disparate portions of the gene resulted in decreased LlIAP mRNA quantities relative to controls. Both nymphs and adult specimens injected with IAP dsRNA exhibited significantly reduced lifespan compared with those injected with non-insect dsRNA (eGFP). Thus, RNAi-mediated knockdown of LlIAP expression has been correlated with a lethal phenotype in adults and nymphs.
-
expression and rna interference of salivary polygalacturonase genes in the tarnished plant bug Lygus lineolaris
Journal of Insect Science, 2010Co-Authors: William B Walker, Margaret L AllenAbstract:Three genes encoding polygalacturonase (PG) have been identified in Lygus lineolaris (Palisot de Beauvois) (Miridae: Hemiptera). Earlier studies showed that the three PG gene transcripts are exclusively expressed in the feeding stages of L. lineolaris. In this report, it is shown that all three transcripts are specifically expressed in salivary glands indicating that PGs are salivary enzymes. Transcriptional profiles of the three PGs were evaluated with respect to diet, comparing live cotton plant material to artificial diet. PG2 transcript levels were consistently lower in cotton-fed insects than those reared on artificial diet. RNA interference was used to knock down expression of PG1 mRNA in adult salivary glands providing the first demonstration of the use of this method in the non-model insect, L. lineolaris.
Fred R. Musser - One of the best experts on this subject based on the ideXlab platform.
-
susceptibility to insecticides and activities of glutathione s transferase and esterase in populations of Lygus lineolaris hemiptera miridae in mississippi
Pest Management Science, 2016Co-Authors: Daniel Fleming, Natraj Krishnan, Angus L Catchot, Fred R. MusserAbstract:BACKGROUND Lygus lineolaris (Palisot de Beauvois) is a serious pest of cotton (Gossypium hirsutum L.) in Mississippi, particularly in the Delta region. This may be due to decreased insecticide susceptibility in that region. Research has revealed populations of L. lineolaris in the Delta region with high levels of insecticide resistance; however, comparisons with populations in the remainder of the state are limited. RESULTS Experiments were undertaken to compare the LC50 values and activities of detoxification enzymes of L. lineolaris populations. The results of these studies indicated that the LC50 values were not different between the Delta and Hills regions, but differences were significant between populations within and across regions. Results of the detoxifying enzyme activity assays revealed significantly higher esterase activity in the Delta region when compared with the Hills. Glutathione S-transferase activity was not different between regions, but differences within and across regions were significant. CONCLUSION The results indicated that glass-vial assays to determine and compare LC50 values may be less accurate than enzymatic assays for detecting insecticide susceptibility differences. Higher esterase activity is likely a contributing factor to the difficulties with managing L. lineolaris in the Mississippi Delta region. © 2015 Society of Chemical Industry.
-
Susceptibility to insecticides and activities of glutathione S‐transferase and esterase in populations of Lygus lineolaris (Hemiptera: Miridae) in Mississippi
Pest management science, 2015Co-Authors: Daniel Fleming, Natraj Krishnan, Angus L Catchot, Fred R. MusserAbstract:BACKGROUND Lygus lineolaris (Palisot de Beauvois) is a serious pest of cotton (Gossypium hirsutum L.) in Mississippi, particularly in the Delta region. This may be due to decreased insecticide susceptibility in that region. Research has revealed populations of L. lineolaris in the Delta region with high levels of insecticide resistance; however, comparisons with populations in the remainder of the state are limited. RESULTS Experiments were undertaken to compare the LC50 values and activities of detoxification enzymes of L. lineolaris populations. The results of these studies indicated that the LC50 values were not different between the Delta and Hills regions, but differences were significant between populations within and across regions. Results of the detoxifying enzyme activity assays revealed significantly higher esterase activity in the Delta region when compared with the Hills. Glutathione S-transferase activity was not different between regions, but differences within and across regions were significant. CONCLUSION The results indicated that glass-vial assays to determine and compare LC50 values may be less accurate than enzymatic assays for detecting insecticide susceptibility differences. Higher esterase activity is likely a contributing factor to the difficulties with managing L. lineolaris in the Mississippi Delta region. © 2015 Society of Chemical Industry.
-
Comparisons of Lygus lineolaris (Hemiptera: Miridae) Populations from Two Distinct Geographical Regions of Mississippi.
Environmental entomology, 2015Co-Authors: Daniel Fleming, R. L. Roehrdanz, K. C. Allen, Fred R. MusserAbstract:The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), is a major pest of cotton (Gossypium hirsutum L.) in the state of Mississippi. Economic data indicate that L. lineolaris is a more serious pest of cotton in the Delta region of Mississippi than in the Hills region; however, little data exist comparing the two populations. Two experiments were undertaken to compare L. lineolaris from these two geographically distinct regions. In the first experiment, colonies of L. lineolaris from each region were reared in the laboratory under controlled conditions and measurements of development time, survivorship, fecundity, and hatch rate were compared. The geographic region of origin had no effect on any of the variables measured; however, the diet used for rearing had a significant effect on all variables except hatch rate. In the second experiment, part of the cox1 gene of the L. lineolaris mitochondrial genome was compared between the two populations to examine possible genetic differences between L. lineolaris from the two regions of Mississippi. Data revealed two cox1 clades in the Delta region and only one cox1 clade in the Hills region. Taken together, the data do not explain the reason for the differences in the severity of damage to cotton in the two regions.
-
Impact of Nosema (Microsporidia) infection and fumagillin treatment on Lygus lineolaris (Hemiptera: Miridae).
Journal of invertebrate pathology, 2012Co-Authors: Fred R. Musser, Kathy S. Knighten, Sarah R. SelfAbstract:Abstract A consistent supply of healthy tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), is necessary for the development of novel management strategies targeting this pest. After being in culture for several years, a substantial portion of a tarnished plant bug colony was found to be infected with a Nosema (Microsporidia) species. Studies were subsequently undertaken to evaluate the impact of Nosema infection on tarnished plant bug productivity and to test the efficacy of fumagillin to treat this infection. Using buffalo black stain, infections could not be reliably detected in adult tarnished plant bugs until adults were 6–8 days post eclosion. Nosema infections reduced adult longevity and fecundity. Maximum fecundity was restored using a concentration of 16.8 ppm fumagillin while maximum longevity for females was at a concentration of 33.6 ppm fumagillin incorporated into the tarnished plant bug diet. Minimum infection scores were obtained at 67.2 ppm, the highest concentration tested. A field survey of tarnished plant bugs in Mississippi found Nosema infections in 3% of wild tarnished plant bugs.
Daniel Fleming - One of the best experts on this subject based on the ideXlab platform.
-
susceptibility to insecticides and activities of glutathione s transferase and esterase in populations of Lygus lineolaris hemiptera miridae in mississippi
Pest Management Science, 2016Co-Authors: Daniel Fleming, Natraj Krishnan, Angus L Catchot, Fred R. MusserAbstract:BACKGROUND Lygus lineolaris (Palisot de Beauvois) is a serious pest of cotton (Gossypium hirsutum L.) in Mississippi, particularly in the Delta region. This may be due to decreased insecticide susceptibility in that region. Research has revealed populations of L. lineolaris in the Delta region with high levels of insecticide resistance; however, comparisons with populations in the remainder of the state are limited. RESULTS Experiments were undertaken to compare the LC50 values and activities of detoxification enzymes of L. lineolaris populations. The results of these studies indicated that the LC50 values were not different between the Delta and Hills regions, but differences were significant between populations within and across regions. Results of the detoxifying enzyme activity assays revealed significantly higher esterase activity in the Delta region when compared with the Hills. Glutathione S-transferase activity was not different between regions, but differences within and across regions were significant. CONCLUSION The results indicated that glass-vial assays to determine and compare LC50 values may be less accurate than enzymatic assays for detecting insecticide susceptibility differences. Higher esterase activity is likely a contributing factor to the difficulties with managing L. lineolaris in the Mississippi Delta region. © 2015 Society of Chemical Industry.
-
Susceptibility to insecticides and activities of glutathione S‐transferase and esterase in populations of Lygus lineolaris (Hemiptera: Miridae) in Mississippi
Pest management science, 2015Co-Authors: Daniel Fleming, Natraj Krishnan, Angus L Catchot, Fred R. MusserAbstract:BACKGROUND Lygus lineolaris (Palisot de Beauvois) is a serious pest of cotton (Gossypium hirsutum L.) in Mississippi, particularly in the Delta region. This may be due to decreased insecticide susceptibility in that region. Research has revealed populations of L. lineolaris in the Delta region with high levels of insecticide resistance; however, comparisons with populations in the remainder of the state are limited. RESULTS Experiments were undertaken to compare the LC50 values and activities of detoxification enzymes of L. lineolaris populations. The results of these studies indicated that the LC50 values were not different between the Delta and Hills regions, but differences were significant between populations within and across regions. Results of the detoxifying enzyme activity assays revealed significantly higher esterase activity in the Delta region when compared with the Hills. Glutathione S-transferase activity was not different between regions, but differences within and across regions were significant. CONCLUSION The results indicated that glass-vial assays to determine and compare LC50 values may be less accurate than enzymatic assays for detecting insecticide susceptibility differences. Higher esterase activity is likely a contributing factor to the difficulties with managing L. lineolaris in the Mississippi Delta region. © 2015 Society of Chemical Industry.
-
Comparisons of Lygus lineolaris (Hemiptera: Miridae) Populations from Two Distinct Geographical Regions of Mississippi.
Environmental entomology, 2015Co-Authors: Daniel Fleming, R. L. Roehrdanz, K. C. Allen, Fred R. MusserAbstract:The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), is a major pest of cotton (Gossypium hirsutum L.) in the state of Mississippi. Economic data indicate that L. lineolaris is a more serious pest of cotton in the Delta region of Mississippi than in the Hills region; however, little data exist comparing the two populations. Two experiments were undertaken to compare L. lineolaris from these two geographically distinct regions. In the first experiment, colonies of L. lineolaris from each region were reared in the laboratory under controlled conditions and measurements of development time, survivorship, fecundity, and hatch rate were compared. The geographic region of origin had no effect on any of the variables measured; however, the diet used for rearing had a significant effect on all variables except hatch rate. In the second experiment, part of the cox1 gene of the L. lineolaris mitochondrial genome was compared between the two populations to examine possible genetic differences between L. lineolaris from the two regions of Mississippi. Data revealed two cox1 clades in the Delta region and only one cox1 clade in the Hills region. Taken together, the data do not explain the reason for the differences in the severity of damage to cotton in the two regions.
