Burkholderia cepacia complex in the rhizosphere:: a minireview

The Burkholderia cepacia complex is a group of closely related bacteria that occurs naturally in water, soil and in the rhizosphere of crop plants. The study of the population dynamics of the B. cepacia complex in natural environments has become an object of growing interest because of the capacity of these bacteria to act both as plant growth promoting, biocontrol and bioremediation agents and as opportunistic human pathogens in immunocompromised patients. The ecological versatility of the B. cepacia complex has been related to its ability to use a wide array of compounds as a carbon source as well as to its particular genomic organization. At present, the B. cepacia complex consists of nine different species and genomovars, which can be recovered at different frequencies from environmental and clinical samples. So far, B. cepacia genomovar 1, B. cepacia genomovar 111, B. vietnamiensis, B. ambifaria and B. pyrrocinia have been recovered from the rhizosphere of several crop plants. Most studies have pointed out the influence of different factors on the distribution and on the degree of genetic polymorphism of rhizosphere natural populations of B. cepacia at complex level. However, at present only scanty data are available on distribution of the different members of the B. cepacia complex in the rhizosphere and their intra-species and genomovar biodiversity.