Role of Pex11p in Lipid Homeostasis in Yarrowia lipolytica

Peroxisomes are essential organelles in the cells of most eukaryotes, from yeasts to mammals. Their role in beta-oxidation is particularly essential in yeasts; for example, in Saccharomyces cerevisiae, fatty acid oxidation takes place solely in peroxisomes. In this species, peroxisome biogenesis occurs when lipids are present in the culture medium, and it involves the Pex11p protein family: ScPex11p, ScPex25p, ScPex27p, and ScPex34p. Yarrowia lipolytica has three Pex11p homologues, which are YALI0C04092p (YlPex11p), YALI0C04565p (YlPex11C), and YALI0D25498p (Pex11/25p). We found that these genes are regulated by oleic acid, and as has been observed in other organisms, YlPEX11 deletion generated giant peroxisomes when mutant yeast were grown in oleic acid medium. Moreover, Delta Ylpex11 was unable to grow on fatty acid medium and showed extreme dose-dependent sensitivity to oleic acid. Indeed, when the strain was grown in minimum medium with 0.5% glucose and 3% oleic acid, lipid body lysis and cell death were observed. Cell death and lipid body lysis may be partially explained by an imbalance in the expression of the genes involved in lipid storage, namely, DGA1, DGA2, and LRO1, as well as that of TGL4, which is involved in lipid remobilization. TGL4 deletion and DGA2 overexpression resulted in decreased oleic acid sensitivity and delayed cell death of Delta Ylpex11, which probably stemmed from the release of free fatty acids into the cytoplasm. All these results show that YlPex11p plays an important role in lipid homeostasis in Y. lipolytica

Erratum to: Identification and characterization of EYK1, a key gene for erythritol catabolism in Yarrowia lipolytica (Applied Microbiology and Biotechnology, (2017), 10.1007/s00253-017-8361-y)

The original article was updated because several pieces of information were omitted. The following paragraph has been added in section Material and methods: Sequences analysis Genome sequences of Yarrowia species were assembled and annotated by Cécile Neuvéglise, Hugo Devillers and coworkers (to be published). Homologs of EYK1 in Yarrowia species were identified by Blast on the private site of GRYC (Genome Resources for Yeast Chromosomes; http://gryc.inra.fr) using EYK1 gene as template and retrieved using the download functionality developed by H. Devillers. The legend of Fig. S1 should be read as follows: Multiple alignments of YALY0F01606g genes with the DAK1, DAK2 and DAK3 in the lipolytica clade. Homologs of EYK1 in Yarrowia species were identified by Blast on the private site of GRYC using EYK1 gene as template and retrieved using the download functionality. Color code: red, similar in all gene; green, similar in two of the three genes; yellow highlighted, different in DAK3 group compared to DAK1 and DAK2 gene. Sequences are from strains YALI: Yarrowia lipolytica CLIB122; YAGA: Yarrowia galli CBS 9722 (96.77%); YAYA: Yarrowia yakushimensis CBS 10253 (91.62%); YAAL: Yarrowia alimentaria CBS 10151 (87.22%) and YAPH: Yarrowia phangngensis CBS 10407 (85.01%). Maximal identities with Yarrowia lipolytica EYK1 (YALI0F01606g) are indicated in bracket. The following information was missing in the Acknowledgements section: The genome sequence of Y. galli was funded by the project CALIN (Carburants Alternatifs et Systèmes d’Injection, grant N° 25331). The genomes of Y. yakushimensis, Y. alimentaria, and Y. phangngensis were funded by INRA in the frame of the AIP-Bioressources 2011 program (YALIP project granted to C. Neuvéglise).SCOPUS: er.jinfo:eu-repo/semantics/publishe

Identification and characterization of EYK1, a key gene for erythritol catabolism in Yarrowia lipolytica

Erythritol is a four-carbon sugar alcohol synthesized by osmophilic yeasts, such as Yarrowia lipolytica, in response to osmotic stress. This metabolite has application as food additive due to its sweetening properties. Although Y. lipolytica can produce erythritol at a high level from glycerol, it is also able to consume it as carbon source. This ability negatively affects erythritol productivity and represents a serious drawback for the development of an efficient erythritol production process. In this study, we have isolated by insertion mutagenesis a Y. lipolytica mutant unable to grow on erythritol. Genomic characterization of the latter highlighted that the mutant phenotype is directly related to the disruption of the YALI0F01606g gene. Several experimental evidences suggested that the identified gene, renamed EYK1, encodes an erythrulose kinase. The mutant strain showed an enhanced capacity to produce erythritol as compared to the wild-type strain. Moreover, in specific experimental conditions, it is also able to convert erythritol to erythrulose, another compound of biotechnological interest