1a. Objectives (from AD-416):
Use a metagenomics approach to identify new viruses infecting the fire ant Solenopsis invicta and subsequently use genomic tools and resources to study the biology (distribution, pathogenicity, etiology, molecular evolutionary history) of several of these viruses.
1b. Approach (from AD-416):
1) Perform a large-scale EST study using 454 pyrosequencing technology to identify potential viruses infecting fire ants using bioinformatics tools and manual annotation of genes. 2) Confirm that newly discovered viruses occur within S. invicta and are not contaminants. 3) Sequence the entire genomes of newly discovered viruses. 4) Use an existing cDNA microarray to determine the host response to viral infections by comparing and identifying genes differentially expressed between virus-infected and uninfected fire ants. 5) Sequence multiple genomes of a single virus and multiple alleles of host genes that respond to viral infection and examine their molecular evolution.
3. Progress Report:
This project is related to and supports Objective 2: Expand current biocontrol efforts by discovering and developing new parasites and pathogens; improving mass culture and field release systems; and defining host specificity of natural enemies. A new virus was discovered. The virus, tentatively named Solenopsis invicta densovirus (SiDNV), represents the first DNA virus discovered in ants (Formicidae) and the first densovirus in a hymenopteran insect. Phylogenetic analysis based on alignments of predicted NS1 protein sequences from densoviruses revealed that SiDNV belongs to a group that includes two other densoviruses found in insects (Acheta domestica densovirus and Planococcus citri densovirus). Molecular-based surveys of fire ants for SiDNV revealed that the virus was prevalent in fire ants from Argentina but completely absent in fire ants found in the U.S.A. indicating that this virus has potential for biological control of introduced fire ants.