ABSTRACT: Genetic diversity of Renibacteriumsalmoninarum was evaluated by multilocus enzyme electrophoresis (MEE). Whole cell lysates were prepared for 40 isolates representing 5 groups based on host and geographic area. Each lysate was assessed for activity of 44 enzymes with a pH 6.5 amine-citrate and a pH 8.0 buffer. Genetic variation was scored at 26 loci. Two zones of activity (presumptive loci) were scored each for esterase (EC 3.1.1.1) and glycyl-leucine peptidase (EC 3.4.11.x). There were no monomorphic loci and there was an average of 2.65 electromorphs per locus. There were 21 electrophoretic types. Mean genetic diversity (H_T) was 0.161 and the percentage of this explained by diversity between groups was G_st = 8.1%; thus 91.9% of the genetic diversity was due to heterogeneity between individual isolates. The 2 groups with the highest genetic diversity were from chinook Oncorhynchustshawytscha and coho O. kisutch salmon, both from the Manistee Weir, Michigan, USA; i.e. 0.270 and 0.298, respectively. The highest genetic diversity for a locus (h_T) was 0.587 for EST-1. At this locus, diversity between groups explained a higher percentage of the total diversity (G_st = 36.5%). Other loci with relatively high genetic diversity were succinate dehydrogenase (0.385; EC 1.3.99.1), cytochrome c oxidase (0.273; EC 1.9.3.1) and aconitase (0.311; EC 4.2.1.3). The results of this study indicate relatively low genetic diversity of R. salmoninarum.

KEY WORDS: Genetic diversity · Renibacteriumsalmoninarum · Electromorphs · Multilocus enzyme electrophoresis · Bacterial kidney disease

Published in DAO Vol. 27, No. 3 (1996) on January 12
ISSN: 0177-5103. Copyright © Inter-Research, Oldendorf/Luhe, 1996