Culture-dependent and culture-independent methods reveal diverse methylotrophic communities in terrestrial environments.

Abstract

One-carbon compounds such as methanol, dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) are significant intermediates in biogeochemical cycles. They are suggested to affect atmospheric chemistry and global climate. Methylotrophic microorganisms are considered as a significant sink for these compounds; therefore, we analyzed the diversity of terrestrial bacteria that utilize methanol, DMS and DMSO as carbon and energy source using culture-dependent and culture-independent methods. The effect of habitat type on the methylotrophic community structure was also investigated in rhizosphere and bulk soil. While thirteen strains affiliated to the genera Hyphomicrobium, Methylobacterium, Pseudomonas, Hydrogenophaga, Rhodococcus, Flavobacterium and Variovorax were isolated, denaturing gradient gel electrophoresis revealed the dominance of Thiobacillus, Rhodococcus, Flavobacterium and Bacteroidetes species. Furthermore, methylotrophic communities that degrade methanol or DMS are not shaped by terrestrial habitat type. Rhizosphere and soil samples showed dominance of Methylophilus spp. and Methylovorus spp. for methanol enrichments; Cytophaga spp., Pseudomonas tremae and Thiobacillus thioparus for DMS enrichments.