Shift of Choline/Betaine Pathway in Recombinant Pseudomonas for Cobalamin Biosynthesis and Abiotic Stress Protection

Balabanova L., Pentekhina I., Nedashkovskaya O., Degtyarenko A., Grigorchuk V., Yugay Y., Vasyutkina E., Kudinova O., Seitkalieva A., Slepchenko L., Son O., Tekutyeva L., Shkryl Y.

В журнале International Journal of Molecular Sciences

Год: 2022 Том: 23 Номер: 22 ArticleID: 13934

The B12-producing strains Pseudomonas nitroreducens DSM 1650 and Pseudomonas sp.CCUG 2519 (both formerly Pseudomonas denitrificans), with the most distributed pathway amongbacteria for exogenous choline/betaine utilization, are promising recombinant hosts for the endogenous production of B12 precursor betaine by direct methylation of bioavailable glycine or nonproteinogenic β-alanine. Two plasmid-based de novo betaine pathways, distinguished by their enzymes, have provided an expression of the genes encoding for N-methyltransferases of the halotolerant cyanobacterium Aphanothece halophytica or plant Limonium latifolium to synthesize the internal glycine betaine or β-alanine betaine, respectively. These betaines equally allowed the recombinantpseudomonads to grow effectively and to synthesize a high level of cobalamin, as well as to increasetheir protective properties against abiotic stresses to a degree comparable with the supplementationof an exogenous betaine. Both de novo betaine pathways significantly enforced the protection of bacterial cells against lowering temperature to 15 °C and increasing salinity to 400 mM of NaCl. However, the expression of the single plant-derived gene for the β-alanine-specific N-methyltransferaseadditionally increased the effectiveness of exogenous glycine betaine almost twofold on cobalamin biosynthesis, probably due to the Pseudomonas' ability to use two independent pathways, their owncholine/betaine pathway and the plant β-alanine betaine biosynthetic pathway.

DOI 10.3390/ijms232213934