Culturable Facultative Methylotrophic Bacteria from the Cactus <i>Neobuxbaumia macrocephala</i> Possess the Locus <i>xoxF</i> and Consume Methanol in the Presence of Ce³⁺ and Ca²⁺

Abstract

Methanol-consuming culturable bacteria were isolated from the plant surface, rhizosphere, and inside the stem of Neobuxbaumia macrocephala. All 38 isolates were facultative methylotrophic microorganisms. Their classification included the Classes Actinobacteria, Sphingobacteriia, Alpha-, Beta-, and Gammaproteobacteria. The deduced amino acid sequences of methanol dehydrogenase obtained by PCR belonging to Actinobacteria, Alpha-, Beta-, and Gammaproteobacteria showed high similarity to rare-earth element (REE)-dependent XoxF methanol dehydrogenases, particularly the group XoxF5. The sequences included Asp301, the REE-coordinating amino acid, present in all known XoxF dehydrogenases and absent in MxaF methanol dehydrogenases. The quantity of the isolates showed positive hybridization with a xoxF probe, but not with a mxaF probe. Isolates of all taxonomic groups showed methylotrophic growth in the presence of Ce3+ or Ca2+. The presence of xoxF-like sequences in methylotrophic bacteria from N. macrocephala and its potential relationship with their adaptability to xerophytic plants are discussed.

Metals and Methanotrophy

“…Environmental significance of Xox-methanol dehydrogenase. Recently, it has been shown that not only are genes encoding Xox-MeDH common to many environmental samples (e.g., see references [147][148][149][150][151][152][153], they exhibit much greater diversity than Mxa-MeDHs (146). Such findings mean that REE-containing MeDHs might in fact be more environmentally relevant than the "classical" or earlier-characterized Mxa-MeDH.…”

Isolation and genomic characterization ofNovimethylophilus kurashikiensisgen. nov. sp. nov., a new lanthanide‐dependent methylotrophic species ofMethylophilaceae

“…Comparative metagenomics also showed that uncultured methylotrophs in the ocean and freshwaters of North America (Ramachandran and Walsh, ) and uncultured lineages of two novel Type I methanotrophs from North Sea sediments (Vekeman et al ., ) possessed only XoxF‐MDH but not MxaFI‐MDH. A quantity of culturable facultative methylotrophic bacteria from the cactus Neobuxbaumia macrocephala showed positive hybridization with a xoxF probe, but not with a mxaF probe, while all these isolates showed methylotrophic growth in the presence of Ce 3+ or Ca 2+ (Del Rocío Bustillos‐Cristales et al ., ). Thus, bacteria that harbor only xoxF but not mxaF may only be isolated in the presence of Ln 3+ .…”

Mixing and matching methylotrophic enzymes to design a novel methanol utilization pathway inE. coli

“…This threshold ensured that only functional homologues were identified (Sangar et al, 2007). Some of the 12 prokaryotic Mdh sequences and 17 eukaryotic Das sequences selected in this way belong to genera known to contain methylotrophs, such as Bacillus, Burkholderia (Chistoserdova et al, 2009), Acinetobacter (Del Rocío Bustillos-Cristales et al, 2017), Pichia and Candida (Supplementary Figure S2). We added an Mdh from Bacillus stearothermophilus and a P. angusta methanol oxidase (MOX), since both have been reported to have good affinity for methanol (Kms of 20 mM and 0.4 mM, respectively) (Shleev et al, 2006; Whitaker et al, 2017).…”