Comparison of parental and transgenic alfalfa rhizosphere bacterial communities using biolog GN metabolic fingerprinting and enterobacterial repetitive intergenic consensus sequence-PCR (ERIC-PCR)

摘要

Rhizosphere bacterial communities of parental and two transgenic lucerne (Medicago sativa) of isogenic background were compared based on metabolic fingerprinting using Biolog GN micro-plates and DNA fingerprinting of bacterial communities present inBiolog GN substrate wells by enterobacterial repetitive intergenic consensus sequence-PCR (ERIC-PCR). The two transgenic lucerne expressed either bacterial (Bacillus licheniformis) genes for alpha-amylase or fungal (Phanerochaete chrysosporium) genes for Mn-dependent lignin peroxidase. Cluster analysis and principal components analysis (PCA) of the Biolog GN metabolic fingerprints indicated consistent differences in substrate utilization between the parental and lignin peroxidase transgenic lucerne rhizosphere bacterial communities. Cluster analysis of ERIC-PCR fingerprints of the bacterial communities in Biolog GN substrate wells revealed consistent differences in the types of bacteria (substrate-specific populations) enriched from the rhizospheres of each lucerne genotype. Comparison of ERIC-PCR fingerprints of bacterial strains obtained from substrate wells to substrate community ERIC-PCR fingerprints suggested that a limited number of populations were responsible for substrate oxidation in thesewells. Results of this study suggest that transgenic plant genotype may affect rhizosphere microorganisms and that the methodology used in this study may prove a useful approach for the comparison of bacterial communities.