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ARS Home » Northeast Area » Leetown, West Virginia » Cool and Cold Water Aquaculture Research » Research » Publications at this Location » Publication #239512
Title: Variable regions in Flavobacterium psychrophilum strains identified by comparative genomics: application to selective breeding for cold water disease resistance

Author
item Wiens, Gregory - Greg
item LAPATRA, SCOTT - Clear Springs Foods, Inc
item Palti, Yniv
item Vallejo, Roger
item Leeds, Timothy - Tim
item Welch, Timothy - Tim
item Rexroad, Caird

Submitted to: American Fishery Society (Fish Health Section) Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/8/2009
Publication Date: 6/8/2009
Citation: Wiens, G.D., Lapatra, S.E., Palti, Y., Vallejo, R.L., Leeds, T.D., Welch, T.J., Rexroad III, C.E. 2009. Variable regions in Flavobacterium psychrophilum strains identified by comparative genomics: application to selective breeding for cold water disease resistance. American Fishery Society (Fish Health Section) Proceedings.

Interpretive Summary: .

Technical Abstract: Bacterial cold water disease is one of the most frequent causes of elevated loss in juvenile salmonids, and the development of effective control strategies is a high priority to aquaculturists, management agencies, and conservationists. Since 2005, rainbow trout (Oncorhynchus mykiss) have been bred at the National Center for Cool and Cold Water Aquaculture for increased cold water disease resistance. We have demonstrated that post-challenge survival, an indicator of resistance, is a moderately heritable trait and there is genetic improvement following one generation of selection. While progress has been made, extensive knowledge gaps exist regarding the molecular diversity of F. psychrophilum farm-isolates and whether disease resistance extends against strains isolated from different geographic locations within the U.S. Recently, the genome sequences of two strains, JIP02/86 and CSF259-93, have been determined and compared. We identified several loci of variability between strains and have developed PCR primers for strain typing. In conjunction with these analyses, we utilized challenge experiments to examine whether strain differences affect disease resistance. Progeny from phenotypically resistant (RxR), susceptible (SxS), or resistant by susceptible (RxS) parents were challenged with strain CSF259-93 and two additional strains of F. psychrophilum. Analysis of 21 day post-challenge survival indicated that both fish genotype and bacterial strain influence disease outcome. These findings highlight the importance of understanding both the mechanisms of host innate disease resistance and pathogen variation. This study also demonstrates the utility of comparative genomics for the identification of variable regions and the development of new strain typing assays.