Figure 2.

Distribution of the phl biosynthetic gene cluster in the P. fluorescens species complex. This neighbour-joining phylogeny is based on an alignment of the concatenated partial sequences of four housekeeping genes (16s rDNA, gyrB, rpoB, rpoD; 2945 nucleotides total) generated using MUSCLE [33]. The phylogenetic tree was generated using PhyML [34] and the distance matrices were calculated by the Jukes-Cantor method. Bootstrap values over 50% (out of 1000 replicates) are indicated at the nodes. The presence of a black square indicates that that strain harbours the phl biosynthetic gene cluster. The three subgroups encompassing DAPG-producing strains are highlighted in color. Letters following the strain names correspond to multilocus phylogenetic groups described by Frapolli and colleagues [35].