Lanthanide (Ln)-dependent XoxF-type methanol dehydrogenase (MDH) genes can be found in bacteria that are not believed to be methylotrophs, and studies on their methylotrophic pathways and their use of Ln are now emerging. Ln-dependent methanol utilization in Bradyrhizobium sp. strain Ce-3, which belongs to the Bradyrhizobium elkanii superclade (clade II), was investigated in this study. Strain Ce-3 was able to grow in a media containing methanol as a sole carbon source and light Ln (L-Ln, i.e., La³⁺, Ce³⁺, Pr³⁺, and Nd³⁺), whereas the strain did not show any growth with Ca²⁺ or the heavy Ln, Sm³⁺. We found that the uptake of L-Ln is enhanced mainly by methanol and L-Ln species, and the strain incorporates each L-Ln species evenly into the cell. The genome of strain Ce-3 encodes the xox cluster for Ln-dependent methanol dehydrogenase (xoxF) and the enzymes participating in the methanol oxidation pathway (xoxG, fldA, and gfaA) and regulation (xoxR), but the gene encoding formate dehydrogenase (FDH) was not found in the cluster. MDH, formaldehyde dehydrogenase, and FDH activities were induced by methanol/Ln. Moreover, expression of the genes on the xox cluster was upregulated by methanol/Ln. Based on these results, we concluded that strain Ce-3 possesses a complete L-Ln-dependent methanol oxidation pathway, which is dissimilar to plant phyllospheric bacteria, Methylobacterium species, with a transport system for L-Ln species.

可以在不被认为是甲基营养菌的细菌中发现依赖镧系元素（Ln）的XoxF型甲醇脱氢酶（MDH）基因，并且目前正在研究它们的甲基营养途径和Ln的使用。Bradyrhizobium sp。中Ln依赖的甲醇利用。这项研究调查了属于Bradyrhizobium elkanii超级包层（clade II）的Ce-3菌株。Ce-3菌株能够在含有甲醇作为唯一碳源和轻Ln（L-Ln，即La ³⁺，Ce ³⁺，Pr ³⁺和Nd ³⁺）的培养基中生长，而菌株确实Ca ²⁺或重Ln，Sm ³⁺均无生长。我们发现，L-Ln的吸收主要通过甲醇和L-Ln物质增强，并且该菌株将每个L-Ln物质均匀地掺入细胞中。Ce-3菌株的基因组编码Ln依赖性甲醇脱氢酶（xoxF）的xox簇以及参与甲醇氧化途径（xoxG，fldA和gfaA）和调节（xoxR）的酶，但编码甲酸脱氢酶（在群集中找不到FDH）。MDH，甲醛脱氢酶和FDH活性由甲醇/ Ln诱导。而且，xox上的基因表达甲醇/ Ln使团簇上调。根据这些结果，我们得出结论，Ce-3菌株具有完整的L-Ln依赖性甲醇氧化途径，该途径与植物叶序细菌，甲基杆菌属物种不同，并且具有L-Ln物种的转运系统。