propagation-homalodisca-coagulata-virus-01-via-homalodisca

Propagation of <em>Homalodisca coagulata virus-01</em> via <em>Homalodisca vitripennis</em> Cell Culture

The glassy-winged sharpshooter (Homalodisca vitripennis) is a highly vagile and polyphagous insect found throughout the southwestern United States. These ...

University of Texas at Tyler

Xylella fastidiosa is the causative agent of Pierce's Disease of grape. No published record of X. fastidiosa genetics in Texas exists despite growing financial risk to the U.S. grape industry, a Texas population of the glassy-winged sharpshooter insect vector (Homalodisca vitripennis) now spreading in California, and evidence that the bacterium is ubiquitous to southern states. Using sequences of conserved gyrB and mopB genes, we have established at least two strains in Texas, grape strain and ragweed strain, corresponding genetically with subsp. piercei and multiplex, respectively. The grape strain in Texas is found in Vitis vinifera varieties, hybrid vines, and wild Vitis near vineyards, whereas the ragweed strain in Texas is found in annuals, shrubs, and trees near vineyards or other areas. RFLP and QRT PCR techniques were used to differentiate grape and ragweed strains with greater efficiency than sequencing and are practical for screening numerous X. fastidiosa isolates for clade identity.

Initial genetic analysis of Xylella fastidiosa in Texas.

The red imported fire ant (RIFA) (Solenopsis invicta Buren), an exotic insect pest in Texas, has become well established throughout the eastern part of the state. More aggressive than native ant species, RIFA gradually have enlarged their range and spread north and west despite intense efforts to stop them. Symbiotic bacteria have an important relationship in the midgut of fourth instar RIFA larvae. However, the presence of symbiotic bacteria in hemolymph has not been explored. In this study, symbiotic bacteria isolated from the hemolymph of fourth instar larvae of RIFA were genetically identified in terms of genus using a partial sequence of the 16S rRNA gene. Using three different primer sets to amplify regions of the gyrA, gyrB, and SG850 genes, multiple species of the genus Bacillus were identified as inhabitants of fire ant hemolymph. Analysis of gyrA gene identified Bacillus cereus with a percentage match of 94.13-99.20% with DNA sequences from GenBank BLAST ( www.ncbi.nih.gov ). Using the gyrB gene, Bacillus species were identified with a percentage match of 95.48% to 100% using DNA sequences from GenBank. Finally, analysis of the SG850 gene identified Bacillus cereus with a percentage match of 96.20% to 99.83% using DNA sequences from GenBank.

Molecular identification of hemolymph-associated symbiotic bacteria in red imported fire ant larvae.

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a vector for the causative agents of Huanglongbing, which threatens citrus production worldwide. This study reports and discusses the first D. citri transcriptomes, encompassing the three main life stages of D. citri, egg, nymph and adult. The transcriptomes were annotated using Gene Ontology (GO) and insecticide-related genes within each life stage were identified to aid the development of future D. citri insecticides. Transcriptome assemblies and other sequence data are available for download at the International Asian Citrus Psyllid Genome Consortium website [http://psyllid.org/download] and at NCBI [http://www.ncbi.nlm.nih.gov/bioproject/29447].

Characterization of the Asian Citrus Psyllid Transcriptome.

Insect bacterial symbionts contribute to many essential biological functions of their hosts and can also influence host fecundity and fitness. The physiological contribution symbionts provide can aid in immune response and xenobiotic detoxification. Both of these immune factors can directly impact strategies aimed at managing insect populations. One biological control strategy that shows promise in insects is the use of single-stranded RNA viruses within the group Dicistroviridae. The Solenopsis invicta Virus (SINV; Dicistroviridae), a ssRNA virus, has been proposed as a potential biological control agent for the urban pest S. invicta Buren or red imported fire ant (RIFA). SINV has been shown to be prevalent in RIFA populations of Texas and Florida; however, mortality is associated with high viral load. In other insect microbe systems, presence of particular bacteria induced resistance against Dicistrovirus. If this type of relationship is present in the RIFA-SINV system, their bacterial community could reduce the effectiveness of SINV as a biological control system. The advantage of 454 pyro-sequencing is that it enables classification of unculturable bacteria. This study examines the bacterial community in brood, workers, and reproductive cast members from colonies with and without SINV infection. Manipulation of the bacterial community may alter virus infection and replication within the mid-gut. Understanding the differences in the microbial community of ant colonies may provide insights that will refine current efforts designing control strategies for this important urban pest.

Bacterial Community Survey of Solenopsis invicta Buren (Red imported fire Ant) Colonies in the Presence and Absence of Solenopsis invicta Virus (SINV).

Article	Year
Initial genetic analysis of Xylella fastidiosa in Texas. Current microbiology\| PubMed ID: 18172717	2008
Molecular identification of hemolymph-associated symbiotic bacteria in red imported fire ant larvae. Current microbiology\| PubMed ID: 18795363	2008
Characterization of the Asian Citrus Psyllid Transcriptome. Journal of genomics\| PubMed ID: 24511328	2014
Bacterial Community Survey of Solenopsis invicta Buren (Red imported fire Ant) Colonies in the Presence and Absence of Solenopsis invicta Virus (SINV). Current microbiology\| PubMed ID: 24934994	2014

Blake R. Bextine

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