FIG. 5.

Neighbor-joining phylogenetic tree of nirK constructed using 44 cloned and partial amino acid sequences of 140 amino acids obtained from the three sites. They were compared with 21 sequences from GenBank and the sequences of our cultivated diazotrophic and denitrifying mangrove root isolates (purple). The clones were designated according to the site they were taken from: site 1, 1K (green); site 2, 2K (red); site 3, 3K (blue). We used the aniA sequence from Neisseria gonorrhoeae (M97926) as an outgroup. Bootstrap values greater than 500 from 1,000 replicate trees are reported at the nodes. The scale represents 10 mutations per 100 amino acid positions.