Fig. 4

Maximum Likelihood phylogeny of the microbial pyridine pathway for nicotine degradation (A) and of the plasmids harbouring the nic-genes cluster B. The nicotine pathway phylogeny was reconstructed from the concatenated purU, pnh, pmfR, ndhL, kdhL gene sequences. The plasmids phylogeny was reconstructed from features postulated to be shared by Paenarthrobacter [19]: the syntenic T4SS system and DNA repeats located 5′ of 3 key ORFs—Duf4192, DprA and ParB. Numbers on branches indicate bootstrap support percentages and values > 70% are shown. The size bar corresponds to 0.1 nucleotide substitutions per site; the length of the dashed lines is not true to scale. Blue colour indicates identical nic-genes cluster; green indicates syntenic nic-genes cluster and orange indicates the presence of 5 nic genes, but the nic-cluster is not syntenic; red indicates plasmids that share a syntenic T4SS and DNA repeats located 5′ of 3 key ORFs—Duf4192, DprA and ParB