Regulation of lanthanide-dependent methanol oxidation pathway in the legume symbiotic nitrogen-fixing bacterium Bradyrhizobium sp. strain Ce-3
Regulation of lanthanide-dependent methanol oxidation pathway in the legume symbiotic nitrogen-fixing bacterium Bradyrhizobium sp. strain Ce-3
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DOI：
10.1016/j.jbiosc.2020.07.012
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发表时间：
2020-12-01
影响因子：
2.8
通讯作者：
Nakagawa, Tomoyuki
中科院分区：
文献类型：
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作者：
Pastawan, Viagian;Suganuma, Soya;Nakagawa, Tomoyuki
镧系元素（Ln）依赖的XoxF型甲醇脱氢酶（MDH）基因可以在不被认为是甲基营养菌的细菌中发现，并且关于其甲基营养途径及其对Ln的使用的研究现在正在出现。研究了埃氏慢生根瘤菌（Bradyrhizobium elkanii）超进化枝（进化枝II）中的慢生根瘤菌Ce-3对甲醇的利用。菌株Ce-3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+）），而Ca ~（2+）或重Ln、Sm ~（3+）对菌株没有任何生长。我们发现，L-Ln的吸收主要是由甲醇和L-Ln物种，并将每个L-Ln物种均匀地纳入细胞。Ce-3菌株的基因组编码Ln依赖型甲醇脱氢酶（xoxF）和参与甲醇氧化途径的酶（xoxG、fldA和gfaA）及调控酶（xoxR）的xox簇，但在该簇中未发现编码甲酸脱氢酶（FDH）的基因。甲醇/Ln诱导MDH、甲醛脱氢酶和FDH活性。此外，xox簇上的基因的表达被甲醇/Ln上调。基于这些结果，我们得出结论，菌株Ce-3具有一个完整的L-Ln依赖的甲醇氧化途径，这是不同的植物叶际细菌，甲基杆菌属物种，与运输系统的L-Ln物种。(C)2020年，生物技术学会，日本。All rights reserved.
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. (C) 2020, The Society for Biotechnology, Japan. All rights reserved.