title: Decomposition of plant-sourced carbon compounds by heterotrophic betaproteobacteria isolated from a tropical Costa Rican bromeliad.
abstract: Betaproteobacteria were the most common isolates from the water-filled tank of a Costa Rican bromeliad. Isolates included eight species from the orders Neisseriales and Burkholderiales, with close relatives recovered previously from tropical soils, wetlands, freshwater, or in association with plants. Compared to close relatives, the isolates displayed high temperature and comparatively low pH optima, reflecting the tropical, acidic nature of the bromeliad tank. Bromeliad-associated bacteria most closely related to Chromobacterium, Herbaspirillum, and Aquitalea were all isolated exclusively at pH 6, while Ralstonia, Cupriavidus, and three species of Burkholderia were isolated mostly at pH 4. Activity profiles for the isolates suggest pervasive capabilities for the breakdown of plant-sourced organics, including d-galacturonic acid, mannitol, d-xylose, and l-phenylalanine, also reflecting a niche dominated by decomposition of leaves from the overlying canopy, which become entrained in the tanks. Metabolic activity profiles were overlapping between the Burkholderiales, isolated at pH 4, and the Neisseriales, isolated at pH 6, suggesting that plant material decomposition, which is presumably the underlying process sustaining the tank community and possibly the plant itself, occurs in the tanks at both pH extremes. These results suggest that bromeliad-associated betaproteobacteria may play an important role in the cycling of carbon in this unusual aquatic habitat.
authors.affiliation: Biology Deptartment, Occidental College, Los Angeles, California.
authors.forename: Jane
authors.initials: J
authors.lastname: Klann
authors.affiliation: Biology Deptartment, Occidental College, Los Angeles, California.
authors.forename: Alexandra
authors.initials: A
authors.lastname: McHenry
authors.affiliation: Biology Deptartment, Occidental College, Los Angeles, California.
authors.forename: Carin
authors.initials: C
authors.lastname: Montelongo
authors.affiliation: Biology Deptartment, Occidental College, Los Angeles, California.
authors.forename: Shana K
authors.initials: SK
authors.lastname: Goffredi
mesh_terms: D020562:Betaproteobacteria / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D044822:Biodiversity; D031229:Bromeliaceae / Q000378:metabolism* / Q000382:microbiology*; D057486:Carbon Cycle / Q000502:physiology; D003364:Costa Rica; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D000071436:Thermotolerance / Q000235:genetics / Q000502:physiology; D014329:Tropical Climate; D014871:Water Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S; D012987:Soil
keywords: Betaproteobacteria; Costa Rica; bromeliad; decomposition; rainforest