Abstract
Procedures for estimating the diversity of Frankia isolates are described. Forty-three alder isolates were separated into six groups by comparing protein patterns obtained during sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE) of whole-cell lysates. Thirty-five of the strains comprised group A and were indistinguishable from one another. Four strains were quite similar to a Comptonia peregrina isolate (CpI1) and were included in group C. Group D had two members and groups B, E, and F each had one member. The groupings were confirmed by hyphal morphology, colony appearance, and carbon source utilization patterns.