Temporal Variation in Genetic Diversity and Structure of a Lotic Population of Burkholderia (Pseudomonas) cepacia

Abstract

The genetic structure and temporal patterns of genetic diversity in a population of Burkholderia (Pseudomonas) cepacia, isolated from a southeastern blackwater stream, were investigated by multilocus enzyme electrophoresis. Allelic variation in seven structural gene loci was monitored at a single stream location at 0, 6, 12, and 24 h and at 2, 4, 8, 16, and 32 days. Over the length of the study, 217 isolates were collected, from which 65 unique electrophoretic types (ETs) were identified. Most of these ETs were present at only one or two time periods and were considered transients; however, one resident ET was particularly abundant (64 of the 217 isolates [29.4%]) and was found at all time points except day 32. The mean genetic diversity of the entire population was 0.520, and the index of association (a measure of multilocus linkage disequilibrium) was 1.33. These results, taken in conjunction with a previous study focusing on spatial patterns of genetic diversity in lotic B. cepacia, show that these bacterial populations exhibit greater variability among sites than within a site over time, suggesting relative stability over short time periods.