Location: Tick and Biting Fly Research
Title: Pyrosequencing-based Analysis of the Microbiome Associated with the Horn Fly, Haematobia Irritans Authors
|Palavesam, Azhahianambi -|
|Perez De Leon, Adalberto|
|Wang, Ju -|
|Dowd, Scott -|
|Sun, Yan -|
|Foil, Lane -|
Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 7, 2012
Publication Date: September 24, 2012
Citation: Palavesam, A., Guerrero, F., Perez De Leon, A.A., Heekin, A.M., Wang, J., Dowd, S., Sun, Y., Foil, L.D. 2012. Pyrosequencing-based analysis of the microbiome associated with the horn fly, Haematobia irritans. PLoS One. 7:44390. Interpretive Summary: The horn fly is an important economic pest of cattle, but little is known of the horn fly's potential as a vector for disease. Traditional microbial culture-based methods are time consuming and many species remain unculturable. Technologies developed over the past decade enable researchers to examine the bacterial diversity associated with arthropods without having to use traditional culture methods. We used a novel pyrosequencing method to carrying out the identification and quantitative analysis of biota in female adult horn flies, male adult horn flies and horn fly eggs. This method identified species-specific DNA sequences in our samples which allowed the identification of various prokaryotic phyla, classes, orders, families, genera and species associated with the fly life stage examined. Bacteria were grouped according to their presence in one, two or all three horn fly life stages tested. The group of bacteria that occurred in only one life stage had the largest diversity of species, but the contribution of this group to the total bacterial load in a life stage was low. Conversely, the group of bacteria detected on all three horn fly life stages had a smaller number of species than the group occurring in only one life stage. However, the group detected in all three life stages contributed a much higher percentage of the total bacterial load than the other groups. Three bacterial species capable of causing diseases of humans or cattle were detected. This technique allowed the rapid detection of species with potential for causing disease in humans or cattle.
Technical Abstract: The horn fly, Haematobia irritans, is one of the economically important pests of cattle. Use of insecticide has been a major element of horn fly management programs. Growing concerns of insecticide resistance, insecticide residues on farm products, and nonavailability of new generation insecticides for the near future, are serious issues for the organized livestock farming industry. Alternative horn fly control methods would reduce the use of insecticides and reduce the amount of insecticide residues on livestock products and give an impetus to the organic livestock farming segment. The horn fly, an obligatory blood feeder, requires the help of microflora to supply additional nutrients and metabolize the blood meal. Recent advancements in DNA sequencing methodologies enable researchers to examine the microflora diversity independent of culture methods. We used the bacterial 16S tag-encoded FLX-titanium amplicon pyrosequencing (bTEFAP) method to carry out the classification analysis of bacterial flora in adult female horn flies, adult male horn flies, and horn fly eggs. The bTEFAP method identified 16S rDNA sequences in our samples which allowed the identification of various prokaryotic taxa associated with the life stage examined. This is the first comprehensive report of bacterial flora associated with horn fly or any other dipteran-pests affecting livestock using a culture-independent method. Several rumen, environmental, symbiotic, and pathogenic bacteria associated with the horn fly were identified and quantified. This is the first report of the presence of Wolbachia in horn flies of USA origin and is the first report of the presence of Rikenella in an obligatory blood feeding insect.