Background
L-ascorbate (Vitamin C) is an important antioxidant and co-factor in eukaryotic cells, and in mammals it is indispensable for brain development and cognitive function. Vertebrates usually become L-ascorbate auxothrophs when the last enzyme of the synthetic pathway, an L-gulonolactone oxidase (
GULO
), is lost. Since Protostomes were until recently thought not to have a
GULO
gene, they were considered to be auxothrophs for Vitamin C.
Results
By performing phylogenetic analyses with tens of non-Bilateria and Protostomian genomes, it is shown, that a
GULO
gene is present in the non-Bilateria Placozoa, Myxozoa (here reported for the first time) and Anthozoa groups, and in Protostomians, in the Araneae family, the Gastropoda class, the Acari subclass (here reported for the first time), and the Priapulida, Annelida (here reported for the first time) and Brachiopoda phyla lineages.
GULO
is an old gene that predates the separation of Animals and Fungi, although it could be much older. We also show that within Protostomes,
GULO
has been lost multiple times in large taxonomic groups, namely the Pancrustacea, Nematoda, Platyhelminthes and Bivalvia groups, a pattern similar to that reported for Vertebrate species. Nevertheless, we show that
Drosophila melanogaster
seems to be capable of synthesizing L-ascorbate, likely through an alternative pathway, as recently reported for
Caenorhabditis elegans
.
Conclusions
Non-Bilaterian and Protostomians seem to be able to synthesize Vitamin C either through the conventional animal pathway or an alternative pathway, but in this animal group, not being able to synthesize L-ascorbate seems to be the exception rather than the rule.
Electronic supplementary material
The online version of this article (10.1186/s12862-019-1454-8) contains supplementary material, which is available to authorized users.
