Gene-centric metegenome analysis reveals diversity of Pseudomonas aeruginosa biofilm gene orthologs in fresh water ecosystem.

Metagenomic analysis of biofilm forming bacteria in environmental samples remains challenging due to the non-availability of gene sequences of most of the uncultivable bacteria. Sequences of Pseudomonas aeruginosa PAO1-UW genes involved either directly or indirectly in biofilm formation were analyzed using BLASTn to obtain matching sequences from different strain, species and genus. Conserved regions in the functional domain of the amino acid sequences were used to design common primers for direct PCR analysis of freshwater metagenomes. Seven key genes such as aceA, clpP, typA, cbrA, phoR, rpoS and gacA involved in biofilm formation were validated. The ortholog genes belonged to wide range of Pseudomonas sp. indicating the diversity of biofilm genes and the conservation of protein functional domains. The approach would also help in analyzing the expression of biofilm genes in different bacteria of freshwater systems for monitoring toxic contaminations such as organic or inorganic pollutants.