Taxonomy and diversity of aldehyde dehydrogenases in bacteria of the Pseudomonas genus
Authors: Julián‐Sánchez Adriana , Riveros‐Rosas Héctor , Moreno‐Hagelsieb Gabriel , Muñoz‐Clares Rosario A. 
Published: June 2021

Aldehyde dehydrogenases (ALDHs) comprise one of the most ancient protein superfamilies widely distributed in the three domains of life. Their members have been extensively studied in animals and plants, sorted out in different ALDH protein families and their participation in a broad variety of metabolic pathways has been documented. Paradoxically, no systematic studies comprising ALDHs from bacteria have been performed despite their extensive metabolic capacity, their ability to produce multiple secondary metabolites, as well as their ability to use various carbon sources. Among bacteria, Pseudomonas is one of the most complex bacterial genera and is currently the genus of Gram‐negative bacteria with the largest number of known species. Pseudomonas include a metabolically versatile group of organisms that occupy numerous ecological niches. For these reasons, we selected the Pseudomonas genus as a paradigm to analyze the diversity of ALDHs in bacteria. With this aim, complete Pseudomonas genome sequences and annotations were retrieved from NCBI's RefSeq genome database. The 258 retrieved Pseudomonas strains belong to 46 different species, along with 23 with no species designation. The genomes of these Pseudomonas strains contain from 3,315 to 6,825 annotated protein coding genes. A total of 6,510 ALDH sequences were found in the selected Pseudomonas strains, with a median of 24 ALDH‐coding genes per strain (by comparison humans possess only 19 different aldh loci). Pseudomonas saudiphocaensis possesses the lowest number of aldh genes (9), but also possesses the smallest proteome (3,315 protein coding genes). In contrast, Pseudomonas pseudoalcaligenes KF707 NBRC110670 possesses the maximum number of aldh genes (49), with a proteome below the average size (5,571 protein coding genes). The ALDHs found in Pseudomonas can be sorted out in 42 protein families, with a predominance of 14 families, which contained 76% of all ALDHs found. In this regard, it is important to note that many Pseudomonas genomes have multiple aldh genes coding for proteins belonging to the same family. Given that all strains contained at least one member of families ALDH4, ALDH5, ALDH6, ALDH14, ALDH18 and ALDH27, we consider these families to be part of the core Pseudomonas genome, and are involved in proline metabolism (ALDH4 and ALDH18), succinate and GABA metabolism (ALDH5), valine and β‐alanine metabolism (ALDH6), ethanol and ethanolamine catabolism (ALDH14), and polyamines and histamine catabolism (ALDH27).Support or Funding InformationFinancially supported by DGAPA‐UNAM (PAPIIT IN225016 & IN218819) grants to HRR, DGAPA‐UNAM (PAPIIT IN220317) and CONACyT 283524 grants to RAMC, and a Discovery Grant from The Natural Sciences and Engineering Research Council of Canada (NSERC) to GMH. HRR was supported by PASPA‐DGAPA, UNAM program.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.