16S ribosomal DNA characterization of nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril)

Abstract

Nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril) were characterized by amplified 16S ribosomal DNA restriction analysis and 16S rRNA sequence analysis. Herbaspirillum seropedicae, Herbaspirillum rubrisubalbicans, Burkholderia brasilensis, and Burkholderia tropicalis were identified. Eight other types were placed in close proximity to these genera and other alpha and beta Proteobacteria.

FIG. 1

Dendrogram inferred from AluI, HaeIII, HinfI, and RsaI restriction pattern data from Y1-Y3 16S rDNA PCR-amplified fragments obtained for the types shown in Table 1. Distances were calculated for all pairwise patterns with Nei-Li coefficient (9), and the dendrogram was established by the unweighted pair-group method with arithmetic average (12).

FIG. 2

Phylogenetic tree inferred for genotype sequences I to X and representative organisms of the alpha and beta subclasses of Proteobacteria available in the GenBank database (accession numbers are in parentheses). The Y1-Y2 region was used to reconstruct the tree by the neighbor-joining method (10) from distances calculated by the method of Jukes and Cantor (6). A bootstrap analysis with 100 repetitions was performed, and only values above 50 are shown. The sequence of E. coli (a member of the gamma subclass of Proteobacteria) was used to root the tree.