Hunter, WB., Hsu, HT. Synthetic Diets Insects 99 by Wayne Hunter
Good Images Wayne.hunter@usda.gov, 1992
Scanning and transmission electron microscopy are used to elucidate the internal morphology of th... more Scanning and transmission electron microscopy are used to elucidate the internal morphology of the feeding structures of the western flower thrips, Frankliniella occidentalis (Thysanoptera : Thripidae). The position of the single mandible and paired maxillary stylets, relative to one another within the mouthcone, are shown through sequential thin sectioning. Observation of thin sections of all 3 stylets demonstrate them to be innervated. Within the mandibular stylet are 3 dendrites extending its length, and 2 lateral dendrites in its wall. Each maxillary stylet contains 4 dendritic canals, each with one dendrite. The location of the cibarium within the mouthcone is examined and the attachments of its dilator muscles are shown. One to 3 dendrites, varying in functional type, are found in each paraglossal sensillum. The ultrastructural evidence presented suggests that some paraglossal sensilla have a dual chemosensory and mechanosensory function, while others are apparently solely mechanosensory. The significance of these findings relative to the feeding mechanisms of thrips and the possible function of stylet and paraglossal sensory structures in host location, feeding site selection and host choice are discussed.
Emani, C., Hunter, WB. 2013. Insect pests exhibit a diverse array of genetic-based responses when... more Emani, C., Hunter, WB. 2013. Insect pests exhibit a diverse array of genetic-based responses when interacting with crop systems; these changes can be in response to pathogens, symbiotic microbes, host plants, chemicals, and the environment. Agricultural research has for decades focused on gathering crucial information on the biochemical , genetic, and molecular realms that deal with plant–insect interactions in changing ecosystems. Environmental conditions, which include the overall conditions of climate change, are a reality that needs to be considered as one of the crucial phenomena of changing ecosystems when planning future crop security and/or pest management strategies. Focused research in documenting the interactions that occur between crop systems and insect pests under changing climates will be a needed addition to current research efforts whose aim is to define future strategies that crop scientists relate to the broader societal concerns of food security in an ever-changing environment. This chapter attempts to integrate the past and present research in classical and molecular breeding, transgenic technology , and pest management within the context of climate change. The integrated approach will direct present research efforts that aim at creating plant–insect pest interaction–climate change models that reliably advise future strategies to develop improved insect-resistant, climate-resilient plant varieties.
Hail, DA, Dowd, S, Hunter, WB, Bextine, BR. 2010. The potato psyllid is the vector of the α-Prote... more Hail, DA, Dowd, S, Hunter, WB, Bextine, BR. 2010. The potato psyllid is the vector of the α-Proteobacteria Candidatus Liberibacter psyllaurous, the causal agent of Zebra Chip in potatoes. The disease is a major limiting factor in both the production and processing of potatoes into chips with no cure. RNAi has the potential to limit the spread and severity of Zebra Chip by reducing the insect load per field per season. Pyrosequencing was used to identify target genes and synthetic dsRNA constructs were designed to block the activity of heat shock protein 70 and heat shock cognate 70. These molecular chaperones are intimately involved in essentially all life processes by folding and stabilizing other proteins. In this study these constructs were tested on potato psyllid cell cultures and morphological evidence showed shriveling and dispersal into the media. We plan to target other genes and deliver RNAi to insects via the plant through a root soaking procedure.
PloS one, 2015
&... more 'Candidatus Liberibacter asiaticus' (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid. Interactions among D. citri and its microbial endosymbionts, including 'Candidatus Profftella armatura', are likely to impact transmission of CLas. We used quantitative mass spectrometry to compare the proteomes of CLas(+) and CLas(-) populations of D. citri, and found that proteins involved in polyketide biosynthesis by the endosymbiont Profftella were up-regulated in CLas(+) insects. Mass spectrometry analysis of the Profftella polyketide diaphorin in D. citri metabolite extracts revealed the presence of a novel diaphorin-related polyketide and the ratio of these two polyketides was changed in CLas(+) insects. Insect proteins differentially expressed between CLas(+) and CLas(-) D. citri included defense and immunity proteins, proteins involved in energy storage and utilization, and proteins involved in endocytosis, cellular adhesion, and cytoskeletal remodeling which are associated with microbial invasion of host cells. Insight into the metabolic interdependence between the insect vector, its endosymbionts, and the citrus greening pathogen reveals novel opportunities for control of this disease, which is currently having a devastating impact on citrus production worldwide.
Genome Mapping Genomics Animals, 2008
Journal of Invertebrate Pathology, 2001
... Principal Investigator: Blake Bextine Dept. of Biology University of Texas, Tyler Tyler, TX 7... more ... Principal Investigator: Blake Bextine Dept. of Biology University of Texas, Tyler Tyler, TX 75799 bbextine@uttyler.edu Co-Principal Investigator: Wayne Hunter USDA, ARS Fort Pierce, FL 34945 wayne.hunter@ars.usda.gov Researchers: Chelsea Swatsell Dept. ...
Page 1. Comparison of Feeding Behavior of the Potato Leafhopper Empoasca fabae (Homoptera: Cicade... more Page 1. Comparison of Feeding Behavior of the Potato Leafhopper Empoasca fabae (Homoptera: Cicadellidae) on Alfalfa and Broad Bean Leaves ELAINE A. BACKUS ANDWAYNE B. HUNTER' Department of Entomology, University of Missouri, Columbia, Missouri65211 ...
We successfully developed Asian citrus psyllid cell cultures as a tool to subculture Canidatus Li... more We successfully developed Asian citrus psyllid cell cultures as a tool to subculture Canidatus Liberibacter asiaticus (Las), which is a fastidious bacterium that reportedly replicates within the psyllid host. This novel approach uses psyllid cell cultures as the medium to isolate and culture this bacterium to permit further research. The Asian Citrus Psyllid (ACP), Diaphorina citri, (Hemiptera: Psyllidae) is a highly competent vector of the phloem-inhabiting bacterium (Las), associated with the disease Huanglongbing (HLB). World-wide HLB has become a major limiting factor to the production of citrus. A specific psyllid cell culture medium was developed during the screening of 12 commercially available insect cell culture media. Attempts were made using starter cells from embryos and midgut tissues. Cells and tissues could be maintained for up to 4 months. The developed psyllid culture medium, Hert-Hunter-70, provided the best growth rates with doubling times at ~ten days. Previous attempts to use a lepidopteran cell culture, Spodoptera frugiperda (Sf9), to culture Liberibacter were unsuccessful, suggesting further that a psyllid cell culture would be more permissive. Psyllid cell cultures are also being used to propagate and study psyllid viral pathogens.
Transmission electron microscopy was used to confirm the presence of picorna-like virus particles... more Transmission electron microscopy was used to confirm the presence of picorna-like virus particles presumed to be Homalodisca coagulata virus-1 (HoCV-1) in the midgut region of adult glassy-winged sharpshooters (GWSS). In addition, we offer a reverse transcription polymerase chain reaction (RT-PCR) assay for the detection of this virus with a sensitivity of 95 genome equivalents. A survey employing this assay in conjunction with GWSS samples collected throughout the USA including California, Hawaii, Florida Georgia, and Carolinas revealed a fairly widespread pattern of distribution, although potentially restricted to temperate regions, areas with elevated host densities, or to populations of a common origin. The virus was found to naturally infect adults regardless of host plant and was not specific to a particular life stage or sex. Examination of alternate leafhopper species demonstrated that, although infection is not ubiquitous to all sharpshooter genera, HoCV-1 is not limited to Homalodisca vitripennis (aka. H. coagulata).
The salivary glands of the Glassy-winged sharpshooter (GWSS),
Homalodisca vitripennis Germar 1821... more The salivary glands of the Glassy-winged sharpshooter (GWSS),
Homalodisca vitripennis Germar 1821, (syn. H. coagulate, Hemiptera: Cicadellidae) were collected and used to produce a cDNA library. Examination by BLASTX analyses identified 2 viral sequences, one a 610-base pair fragment and a second 839-base pair fragment, both of which had significant homology to viruses within the genus Phytoreovirus . Resequencing of the fragments confirmed sequence validities. These sequences were used for in silico protein translation and BLASTP analysis confirming the established homology. While the GWSS is the primary vector of Pierce’s disease of grapes, this is the first report that GWSS may be a vector of phytoreoviruses. Phytoreoviruses are transmitted in a propagative manner by cicadellid leafhoppers (Hemiptera: Cicadellidae), which acquire and transmit them during feeding. phytoreoviruses have been reported from Agallian, Agalliopsis, Nephotettix , and Recilia , genera of leafhoppers, with evidence for transovarial transmission. The GWSS, although considered to feed primarily from the xylem, ingests from other plant tissues, such as the phloem and mesophyll during probing similar to other leafhoppers. Monitoring for an increase of Phytoreovirus spread in graminaceous crops that are in proximity to vineyards or tree crop orchards, where GWSS occurs, such as in southern California, will provide a better understanding of the potential role of the GWSS as a disease vector in the spread of phytoreoviruses and other plant pathogens. Sequences have been deposited in NCBI database under accession numbers (EF058280) for GWSS-V1, WHSg013C11 and (EF058281) for GWSS-V2, WHSg024H02.
The complete nucleotide sequence of a novel single-stranded RNA virus infecting the glassy-winged... more The complete nucleotide sequence of a novel single-stranded RNA virus infecting the glassy-winged sharpshooter, Homalodisca coagulata, has been determined. In silico analysis of H. coagulata virus-1 (HoCV-1) revealed a 9321-nt polyadenylated genome encoding two large open reading frames (ORF1 and ORF2) separated by a 182-nt intergenic region (IGR). The deduced amino acid sequence of the 5′-proximal ORF (ORF1, nt 420–5807) exhibited conserved core motifs characteristic of the helicases, cysteine proteases, and RNA-dependent RNA polymerases of other insect-infecting picorna-like viruses. A structural model created using Mfold exposed a series of stem loop (SL) structures immediately preceding the second ORF which are analogous to an internal ribosome entry site (IRES), suggesting that ORF2 begins with a noncognate GCA triplet rather than the canonical AUG. This 3′ ORF2 (5990–8740) showed significant similarity to the structural proteins of members of the family Dicistroviridae, particularly those belonging to the genus Cripavirus. Evidence demonstrating relatedness of these viruses regarding genome organization, amino acid sequence similarity, and putative replication strategy substantiate inclusion of HoCV-1 into this taxonomic position.
Two methods used for the clearing of gut contents for plant-feeding hemipterans were evaluated: ... more Two methods used for the clearing of gut contents for plant-feeding hemipterans were evaluated: (i) non-viral host
feeding and (ii) artificial diet feeding by monitoring the
permanence of ingested plant mRNA transcripts within
non-viruliferous and viruliferous insects. Results show that typical RNA transcripts are more stable in the alimentary canal of phloem feeders such as whiteflies (and potentially other hemipterans) than was previous thought.
Begomoviruses have complex associations with their whitefly vecotrs. Analyses showed that Tomato ... more Begomoviruses have complex associations with their whitefly vecotrs. Analyses showed that Tomato Yellow Leaf Curl Virus, replicated within the whitefly Bemisia tabaci, while the Tomato mottle virus, did not. TYLCV also reduce the fitness of B. tabaci, but ToMoV did not.
We report the first discovery and genome sequence of a virus infecting the red imported fire ant,... more We report the first discovery and genome sequence of a virus infecting the red imported fire ant, Solenopsis invicta. The 8026 nucleotide, polyadenylated, RNA genome encoded two large open reading frames (ORF1 and ORF2), flanked and separated by 27, 223, and 171 nucleotide untranslated regions, respectively. The predicted amino acid sequence of the 5Vproximal ORF1 (nucleotides 28 to 4218) exhibited significant identity and possessed consensus sequences characteristic of the helicase, cysteine protease, and RNA-dependent RNA polymerase sequence motifs from picornaviruses, picorna-like viruses, comoviruses, caliciviruses, and sequiviruses. The predicted amino acid sequence of the 3Vproximal ORF2 (nucleotides 4390–7803) showed similarity to structural proteins in picorna-like viruses, especially the acute bee paralysis virus. Electron microscopic examination of negatively stained samples from virus-infected fire ants revealed isometric particles with a diameter of 31 nm, consistent with Picornaviridae. A survey for the fire ant virus from areas around Florida revealed a pattern of fairly widespread distribution. Among 168 nests surveyed, 22.9% were infected. The virus was found to infect all fire ant caste members and developmental stages, including eggs, early (1st–2nd) and late (3rd–4th) instars, worker pupae, workers, sexual pupae, alates (h and U), and queens. The virus, tentatively named S. invicta virus (SINV-1), appears to belong to the picorna-like viruses. We did not observe any perceptible symptoms among infected nests in the field. However, in every case where an SINV-1-infected colony was excavatedfrom the field with an inseminated queen and held in the laboratory, all of the brood in these colonies died within 3 months.
The botanical product RD-Repelin, was highly repellent to pea aphids at 1%, 4%, or 10% concentrat... more The botanical product RD-Repelin, was highly repellent to pea aphids at 1%, 4%, or 10% concentrations. Repellency occurred prior to leaf contact by aphids at all concentrations. RD-Repelin delayed symptom expression of ZYMV in 81% of plants treated with 1% concentrations, although virus transmission was not prevented. The effects of RD-Repellin on aphid settling behavior, symptom expression and potenital for pest management are discussed.
Probing behaviors of the potato leafhopper Empoasca fabae (Harris), were studied using an AC elec... more Probing behaviors of the potato leafhopper Empoasca fabae (Harris), were studied using an AC electronic monitor. Observations on two artificial media, water-sucrose and agar-sucrose, revealed three waveforms correlated with probing behaviors. These results plus thin-layer chromatography of the host plants and insects show that the potato leafhopper like many other typhlocybines, does not ingest strictly from the phloem but also from the mesophyll.
The brown citrus aphid, Toxoptera citricida (Kirkaldy), is considered the primary vector of citru... more The brown citrus aphid, Toxoptera citricida (Kirkaldy), is considered the primary vector of citrus tristeza virus, a severe pathogen which causes losses to citrus industries worldwide. The alate (winged) form of this aphid can readily fly long distances with the wind, thus spreading citrus tristeza virus in citrus growing regions. To better understand the biology of the brown citrus aphid and the emergence of genes expressed during wing development, we undertook a large-scale 5' end sequencing project of cDNA clones from alate aphids. Similar large-scale expressed sequence tag (EST) sequencing projects from other insects have provided a vehicle for answering biological questions relating to development and physiology. Although there is a growing database in GenBank of ESTs from insects, most are from Drosophila melanogaster and Anopheles gambiae, with relatively few specifically derived from aphids. However, important morphogenetic processes are exclusively associated with piercing-sucking insect development and sap feeding insect metabolism. In this paper, we describe the first public data set of ESTs from the brown citrus aphid, T. citricida. The cDNA library was derived from alate adults due to their significance in spreading viruses (e.g., citrus tristeza virus). Over 5180 cDNA clones were sequenced, resulting in 4263 high-quality ESTs. Contig alignment of these ESTs resulted in 2124 total assembled sequences, including both contiguous sequences and singlets. Approximately 33% of the ESTs currently have no significant match in either the non-redundant protein or nucleic acid databases. Sequences returning matches with an E-value of ≤ -10 using BLASTX, BLASTN, or TBLASTX were annotated based on their putative molecular function and biological process using the Gene Ontology classification system. These data will aid research efforts in the identification of important genes within insects, specifically aphids and other sap feeding insects within the Order Hemiptera
Scanning electron microscopy was used to elucidate the morphology and sequential movement of thri... more Scanning electron microscopy was used to elucidate the morphology and sequential movement of thrips feeding structures in the 2 species, Frankliniella occidentalis and F. schultzei, (Thysanoptera : Thripidae). The mouthcone consists of paired paraglossae, and fringed labral pad, a single, apically fused mandible and a pair of interlocking maxillae. The maxillae are open apically and form a feeding tube. Ten pairs of sensory pegs of 3 distinct morphological types (sensilla basiconica with a cuticular collar, sensilla basiconica without a cuticular collar, and sensilla trichoidea) were found on the paraglossae. The possible function of these sensory structures in host finding and choice are discussed. No structure for rasping the leaf's surface was found on the mouthcone or the ventral surface of the insect. Live specimens were observed feeding through Parafilm on artificial media (sucrose solution) and lettuce leaf tissue. These observations support earlier findings that thrips feed by piercing leaf cells with the mandible and ingesting cell contents through the feeding tube formed by the maxillary stylets. Based on these findings, we suggest that thrips be classified as piercing-sucking rather than rasping-sucking insects.
An in vitro feeding method for acquisistion of impatiens necrotic spot tospovirus and tomato spot... more An in vitro feeding method for acquisistion of impatiens necrotic spot tospovirus and tomato spotted wilt tospovirus by western flower thrips (Frankliniella occidentalis (Pegande) was develped. This is the first system developed in which tospovirus viability was maintained in an in vitro technique specifically designed for thips feeding. Thrips were caged within a tube cage, with parafilm covering both ends. Leaf extracts from virus infected N. benthamiana or Datura stramoniium were prepared. Following one cycle of differential centrifugation, the extract was placed on the membrane and a second membrane placed over the liquid, thus securing the plant extract between two parafilm membranes. After 24 h acquisition access feeding period thrips were kept on green bean pods until 10 d old. ELISA analyses showed that acquisition feeding of virus suspensions prepared from infected plants resulted in positively detected virus in thrips.
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Hunter, WB., Hsu, HT. Synthetic Diets Insects 99 by Wayne Hunter
Homalodisca vitripennis Germar 1821, (syn. H. coagulate, Hemiptera: Cicadellidae) were collected and used to produce a cDNA library. Examination by BLASTX analyses identified 2 viral sequences, one a 610-base pair fragment and a second 839-base pair fragment, both of which had significant homology to viruses within the genus Phytoreovirus . Resequencing of the fragments confirmed sequence validities. These sequences were used for in silico protein translation and BLASTP analysis confirming the established homology. While the GWSS is the primary vector of Pierce’s disease of grapes, this is the first report that GWSS may be a vector of phytoreoviruses. Phytoreoviruses are transmitted in a propagative manner by cicadellid leafhoppers (Hemiptera: Cicadellidae), which acquire and transmit them during feeding. phytoreoviruses have been reported from Agallian, Agalliopsis, Nephotettix , and Recilia , genera of leafhoppers, with evidence for transovarial transmission. The GWSS, although considered to feed primarily from the xylem, ingests from other plant tissues, such as the phloem and mesophyll during probing similar to other leafhoppers. Monitoring for an increase of Phytoreovirus spread in graminaceous crops that are in proximity to vineyards or tree crop orchards, where GWSS occurs, such as in southern California, will provide a better understanding of the potential role of the GWSS as a disease vector in the spread of phytoreoviruses and other plant pathogens. Sequences have been deposited in NCBI database under accession numbers (EF058280) for GWSS-V1, WHSg013C11 and (EF058281) for GWSS-V2, WHSg024H02.
feeding and (ii) artificial diet feeding by monitoring the
permanence of ingested plant mRNA transcripts within
non-viruliferous and viruliferous insects. Results show that typical RNA transcripts are more stable in the alimentary canal of phloem feeders such as whiteflies (and potentially other hemipterans) than was previous thought.
Homalodisca vitripennis Germar 1821, (syn. H. coagulate, Hemiptera: Cicadellidae) were collected and used to produce a cDNA library. Examination by BLASTX analyses identified 2 viral sequences, one a 610-base pair fragment and a second 839-base pair fragment, both of which had significant homology to viruses within the genus Phytoreovirus . Resequencing of the fragments confirmed sequence validities. These sequences were used for in silico protein translation and BLASTP analysis confirming the established homology. While the GWSS is the primary vector of Pierce’s disease of grapes, this is the first report that GWSS may be a vector of phytoreoviruses. Phytoreoviruses are transmitted in a propagative manner by cicadellid leafhoppers (Hemiptera: Cicadellidae), which acquire and transmit them during feeding. phytoreoviruses have been reported from Agallian, Agalliopsis, Nephotettix , and Recilia , genera of leafhoppers, with evidence for transovarial transmission. The GWSS, although considered to feed primarily from the xylem, ingests from other plant tissues, such as the phloem and mesophyll during probing similar to other leafhoppers. Monitoring for an increase of Phytoreovirus spread in graminaceous crops that are in proximity to vineyards or tree crop orchards, where GWSS occurs, such as in southern California, will provide a better understanding of the potential role of the GWSS as a disease vector in the spread of phytoreoviruses and other plant pathogens. Sequences have been deposited in NCBI database under accession numbers (EF058280) for GWSS-V1, WHSg013C11 and (EF058281) for GWSS-V2, WHSg024H02.
feeding and (ii) artificial diet feeding by monitoring the
permanence of ingested plant mRNA transcripts within
non-viruliferous and viruliferous insects. Results show that typical RNA transcripts are more stable in the alimentary canal of phloem feeders such as whiteflies (and potentially other hemipterans) than was previous thought.