Autotrophic methylotrophy with no methanol dehydrogenase (MDH) in a strain of fluorescent Pseudomonas


Abstract

Background.

Very few true Pseudomonas methylotrophic strains have been described, and in none of them have the pathways for one-carbon (C 1 ) substrate metabolism been elucidated.

Methods.

The genomes of three Pseudomonas strains able to grow on methanol as the sole source of carbon (C) and energy (E) were sequenced and analyzed, and one of the strains was further characterized at the proteomic and physiological level.

Results.

None of the three strains possesses a classic methanol dehydrogenase enzyme, and they apparently employ generalist type-I alcohol dehydrogenases (ADHs) to catabolize methanol to formaldehyde. In two of the strains’ genomes, the only complete route encoded for incorporating methylotrophic carbon is the Calvin-Benson-Bassham (CBB) cycle, while other more typical pathways for C1-carbon assimilation (serine cycle, ribulose monophosphate cycle) appear incomplete. The indispensability of the QedA1 alcohol dehydrogenase and of ribulose bisphosphate carboxylase for growth on methanol was demonstrated by insertion mutagenesis of the qedA1 and cbbL genes in one of the strains.

Discussion.

To the author’s knowledge, all wild-type methylotrophic Pseudomonadota (i.e., “Gram-negative bacteria”) so far described employ a specific dehydrogenase distinctively adapted to using methanol as a substrate (MxaFI, XoxFI, or Mdh2). The methylotrophic Pseudomonas strains described here lack MDH and employ generalist ADHs, thus demoting MDH from the position of a critical enzyme for methanol utilization and expanding the range of enzymes (and genes) that enable methylotrophy in Nature. The second remarkable result of this work is the discovery of the utilization of the CBB cycle by a Pseudomonas strain during methylotrophic growth, an absolute novelty for this very relevant bacterial genus.

Ask to review this manuscript

Notes for potential reviewers

  • Volunteering is not a guarantee that you will be asked to review. There are many reasons: reviewers must be qualified, there should be no conflicts of interest, a minimum of two reviewers have already accepted an invitation, etc.
  • This is NOT OPEN peer review. The review is single-blind, and all recommendations are sent privately to the Academic Editor handling the manuscript. All reviews are published and reviewers can choose to sign their reviews.
  • What happens after volunteering? It may be a few days before you receive an invitation to review with further instructions. You will need to accept the invitation to then become an official referee for the manuscript. If you do not receive an invitation it is for one of many possible reasons as noted above.

  • PeerJ does not judge submissions based on subjective measures such as novelty, impact or degree of advance. Effectively, reviewers are asked to comment on whether or not the submission is scientifically and technically sound and therefore deserves to join the scientific literature. Our Peer Review criteria can be found on the "Editorial Criteria" page - reviewers are specifically asked to comment on 3 broad areas: "Basic Reporting", "Experimental Design" and "Validity of the Findings".
  • Reviewers are expected to comment in a timely, professional, and constructive manner.
  • Until the article is published, reviewers must regard all information relating to the submission as strictly confidential.
  • When submitting a review, reviewers are given the option to "sign" their review (i.e. to associate their name with their comments). Otherwise, all review comments remain anonymous.
  • All reviews of published articles are published. This includes manuscript files, peer review comments, author rebuttals and revised materials.
  • Each time a decision is made by the Academic Editor, each reviewer will receive a copy of the Decision Letter (which will include the comments of all reviewers).

If you have any questions about submitting your review, please email us at [email protected].