Species-speci¢c distribution of a modular family 19 chitinase gene in Burkholderia gladioli

The chitinase gene chiB of Burkholderia gladioli strain CHB101 is the first family 19 chitinase gene found in bacteria other than Streptomyces. The presence of chitinase genes homologous to the chiA (family 18) and chiB (family 19) of B. gladioli strain CHB101 was investigated in closely related species Burkholderia andropogonis, Burkholderia caryophylli, Burkholderia glumae, Burkholderia plantarii, and Burkholderia cepacia as well as in other strains of B. gladioli. Twenty-seven of the 30 strains of B. gladioli examined produced chitinases and were all positive when probed with chiA and chiB of CHB101, although the restriction fragment length polymorphism patterns in these strains were not necessarily identical to that of CHB101. The remaining three strains of B. gladioli and all strains of the other Burkholderia species tested showed no chitinase activity and gave no signal with the chiA or chiB probes. Analysis of the 16S rDNA sequence indicated that the three chitinase-negative strains of B. gladioli were phylogenetically closer to B. glumae or B. cepacia than to B. gladioli, and should therefore be reassigned. Apparently, possession of a modular family 19 chitinase gene homologous to chiB of CHB101 is a species-specific characteristic of B. gladioli. In this article, we show the species-specific distribution of a family 19 chitinase gene in B. gladioli. ß 200