Distinctive Bacterial Communities in the Rhizoplane of Four Tropical Tree Species

• Published in: Microbial ecology Vol. 64; no. 4; pp. 1018 - 1027
• Main Authors: Oh, Yoon Myung, Kim, Mincheol, Lee-Cruz, Larisa, Lai-Hoe, Ang, Go, Rusea, Ainuddin, N., Rahim, Raha Abdul, Shukor, Noraini, Adams, Jonathan M.
• Format: Journal Article
• Language: English
• Published: New York Springer Science + Business Media 01-11-2012; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Acid soils; Acidobacterium; Agathis; Agricultural soils; Bacteria; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Bacteroidetes - classification; Bacteroidetes - genetics; Bacteroidetes - isolation & purification; Betaproteobacteria - classification; Betaproteobacteria - genetics; Betaproteobacteria - isolation & purification; Biological and medical sciences; Biomedical and Life Sciences; Burkholderia; Coniferophyta - growth & development; Coniferophyta - microbiology; DNA, Bacterial - analysis; DNA, Bacterial - genetics; Ecology; Ecosystem; Forest soils; Fundamental and applied biological sciences. Psychology; Genes, rRNA; Geoecology/Natural Processes; Gnetum gnemon; Indigenous species; Life Sciences; Malaysia; Microbial Ecology; Microbiology; Molecular Sequence Data; Nature Conservation; Nutrient cycles; Nutrient uptake; Ordination; Plant diversity; PLANT MICROBE INTERACTIONS; Plant roots; Plant species; Plants; Rainforests; Relative abundance; Rhizoplane; Rhizosphere; RNA, Ribosomal, 16S - genetics; Sequence Analysis, DNA - methods; Soil bacteria; Soil samples; Soils; Species diversity; Species Specificity; Streptophyta - growth & development; Streptophyta - microbiology; Trees; Trees - microbiology; Tropical Climate; Tropical forests; Water Quality/Water Pollution; Malaysia; Bacterial Community; Tree Species; Fine Root; Bulk Soil; Root Surface; Ecology; Microbial community
• ISSN: 0095-3628; 1432-184X
• DOI: 10.1007/s00248-012-0082-2

It is known that the microbial community of the rhizosphere is not only influenced by factors such as root exudates, phenology, and nutrient uptake but also by the plant species. However, studies of bacterial communities associated with tropical rainforest tree root surfaces, or rhizoplane, are lacking. Here, we analyzed the bacterial community of root surfaces of four species of native trees, Agathis borneensis, Dipterocarpus kerrii, Dyera costulata, and Gnetum gnemon, and nearby bulk soils, in a rainforest arboretum in Malaysia, using 454 pyrosequencing of the 16S rRNA gene. The rhizoplane bacterial communities for each of the four tree species sampled clustered separately from one another on an ordination, suggesting that these assemblages are linked to chemical and biological characteristics of the host or possibly to the mycorrhizal fungi present. Bacterial communities of the rhizoplane had various similarities to surrounding bulk soils. Acidobacteria, Alphaproteobacteria, and Betaproteobacteria were dominant in rhizoplane communities and in bulk soils from the same depth (0-10 cm). In contrast, the relative abundance of certain bacterial lineages on the rhizoplane was different from that in bulk soils: Bacteroidetes and Betaproteobacteria, which are known as copiotrophs, were much more abundant in the rhizoplane in comparison to bulk soil. At the genus level, Burkholderia, Acidobacterium, Dyella, and Edaphobacter were more abundant in the rhizoplane. Burkholderia, which are known as both pathogens and mutualists of plants, were especially abundant on the rhizoplane of all tree species sampled. The Burkholderia species present included known mutualists of tropical crops and also known N fixers. The host-specific character of tropical tree rhizoplane bacterial communities may have implications for understanding nutrient cycling, recruitment, and structuring of tree species diversity in tropical forests. Such understanding may prove to be useful in both tropical forestry and conservation.