ABSTRACT
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.
Subject(s)
Ants/microbiology , Bacillus/classification , Bacillus/isolation & purification , Hemolymph/microbiology , Symbiosis , Animals , Bacterial Physiological Phenomena , DNA Gyrase/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Genes, rRNA , Larva/microbiology , Molecular Sequence Data , Phylogeny , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid , TexasABSTRACT
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.
