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Use of rare‐earth elements in the phyllosphere colonizer Methylobacterium extorquens PA1
Author(s) -
Ochsner Andrea M.,
Hemmerle Lucas,
Vonderach Thomas,
Nüssli Ralph,
BortfeldMiller Miriam,
Hattendorf Bodo,
Vorholt Julia A.
Publication year - 2019
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14208
Subject(s) - phyllosphere , biology , arabidopsis , methylobacterium , methanol dehydrogenase , arabidopsis thaliana , alcohol dehydrogenase , transmembrane protein , biochemistry , gene , mutant , genetics , enzyme , receptor , bacteria , 16s ribosomal rna
Summary Until recently, rare‐earth elements (REEs) had been thought to be biologically inactive. This view changed with the discovery of the methanol dehydrogenase XoxF that strictly relies on REEs for its activity. Some methylotrophs only contain xoxF , while others, including the model phyllosphere colonizer Methylobacterium extorquens PA1, harbor this gene in addition to mxaFI encoding a Ca 2+ ‐dependent enzyme. Here we found that REEs induce the expression of xoxF in M . extorquens PA1, while repressing mxaFI , suggesting that XoxF is the preferred methanol dehydrogenase in the presence of sufficient amounts of REE. Using reporter assays and a suppressor screen, we found that lanthanum (La 3+ ) is sensed both in a XoxF‐dependent and independent manner. Furthermore, we investigated the role of REEs during Arabidopsis thaliana colonization. Element analysis of the phyllosphere revealed the presence of several REEs at concentrations up to 10 μg per g dry weight. Complementary proteome analyses of M. extorquens PA1 identified XoxF as a top induced protein in planta and a core set of La 3+ ‐regulated proteins under defined artificial media conditions. Among these was a REE‐binding protein that is encoded next to a gene for a TonB‐dependent transporter. The latter was essential for REE‐dependent growth on methanol indicating chelator‐assisted uptake of REEs.