Molecular Evidence for Novel Planctomycete Diversityin a Municipal Wastewater TreatmentPlant

• Published in: Applied and environmental microbiology Vol. 69; no. 12; pp. 7354 - 7363
• Main Authors: Chouari, Rakia, Le Paslier, Denis, Daegelen, Patrick, Ginestet, Philippe, Weissenbach, Jean, Sghir, Abdelghani
• Format: Journal Article
• Language: English
• Published: 01-12-2003
• ISSN: 0099-2240; 1098-5336
• DOI: 10.1128/AEM.69.12.7354-7363.2003

We
examined anoxic and aerobic basins and an anaerobic digestor of a
municipal wastewater treatment plant for the presence of novel
planctomycete-like diversity. Three 16S rRNA gene libraries were
constructed by using a 16S rRNA-targeted universal reverse primer and a
forward PCR primer specific for
Planctomycetes
. Phylogenetic
analysis of 234 16S rRNA gene sequences defined 110 operational
taxonomic units. The majority of these sequences clustered with the
four known genera,
Pirellula
(32%),
Planctomyces
(18.4%),
Gemmata
(3.8%),
and
Isosphaera
(0.4%). More interestingly, 42.3%
of the sequences appeared to define two distantly separated
monophyletic groups. The first group, represented by 35.5% of
the sequences, was related to the
Planctomyces
group and
branched as a monophyletic cluster. It exhibited between 11.9 and
20.3% 16S rRNA gene sequence dissimilarity in comparisons with
cultivated planctomycetes. The second group, represented by 6.8%
of the sequences, was deeply rooted within the
Planctomycetales
tree. It was distantly related to the anammox
sequences (level of dissimilarity, 20.3 to 24.4%) and was a
monophyletic cluster. The retrieved sequences extended the
intralineage phylogenetic depth of the
Plantomycetales
from 23
to 30.6%. The lineages described here may have a broad diversity
of undiscovered biochemical and metabolic novelty. We
developed a new 16S rRNA-targeted oligonucleotide probe and localized
members of one of the phylogenetic groups using the fluorescent in situ
hybridization technique. Our results indicate that activated sludge
contains very diverse representatives of this group, which grow under
aerobic and anoxic conditions and even under anaerobic conditions. The
majority of species in this group remain poorly
characterized.