dc.contributor.author	Ortiz-Merino, Raúl A.
dc.contributor.author	Kuanyshev, Nurzhan
dc.contributor.author	Byrne, Kevin P.
dc.contributor.author	Varela, Javier A.
dc.contributor.author	Morrissey, John P.
dc.contributor.author	Porro, Danilo
dc.contributor.author	Wolfe, Kenneth H.
dc.contributor.author	Branduardi, Paola
dc.contributor.funder	FP7 People: Marie-Curie Actions
dc.date.accessioned	2018-02-20T11:29:59Z
dc.date.available	2018-02-20T11:29:59Z
dc.date.issued	2017-12-21
dc.description.abstract	Lactic acid has a wide range of applications starting from its undissociated form, and its production using cell factories requires stress-tolerant microbial hosts. The interspecies hybrid yeast Zygosaccharomyces parabailii has great potential to be exploited as a novel host for lactic acid production, due to high organic acid tolerance at low pH, and a fermentative metabolism with a fast growth rate. Here we used RNA-seq to analyze Z. parabailii's transcriptional response to lactic acid added exogenously, and we explore the biological mechanisms involved in tolerance. Z. parabailii contains two homeologous copies of most genes. Under lactic acid stress, the two genes in each homeolog pair tend to diverge in expression to a significantly greater extent than in control conditions, indicating that stress tolerance is facilitated by interactions between the two gene sets in the hybrid. Lactic acid induces downregulation of genes related to cell wall and plasma membrane functions, possibly altering the rate of diffusion of lactic acid into cells. Genes related to iron transport and redox processes were upregulated, suggesting an important role for respiratory functions and oxidative stress defense. We found differences in the expression profiles of genes putatively regulated by Haa1 and Aft1/2, previously described as lactic acid-responsive in Saccharomyces cerevisiae. Furthermore, formate dehydrogenase (FDH) genes form a lactic acid-responsive gene family that has been specifically amplified in Z. parabailii as compared to other closely related species. Our study provides a useful starting point for the engineering of Z. parabailii as a host for lactic acid production.Importance Hybrid yeasts are important in biotechnology because of their tolerance to harsh industrial conditions. The molecular mechanisms of tolerance can be studied by analyzing differential gene expression in conditions of interest, and relating gene expression patterns to protein functions. However, hybrid organisms present a challenge to the standard use of mRNA sequencing (RNA-seq) to study transcriptional responses to stress, because their genomes contain two similar copies of almost every gene. Here we used stringent mapping methods and a high-quality genome sequence to study the transcriptional response to lactic acid stress in Zygosaccharomyces parabailii ATCC60483, a natural interspecies hybrid yeast that contains two complete subgenomes that are approximately 7% divergent in sequence. Beyond the insights we gained into lactic acid tolerance in this study, the methods we developed will be broadly applicable to other yeast hybrid strains.	en
dc.description.status	Peer reviewed	en
dc.description.version	Accepted Version	en
dc.format.mimetype	application/pdf	en
dc.identifier.articleid	e02294-17
dc.identifier.citation	Ortiz-Merino, R. A., Kuanyshev, N., Byrne, K. P., Varela, J. A., Morrissey, J. P., Porro, D., Wolfe, K. H. and Branduardi, P. (2017) 'Transcriptional response to lactic acid stress in the hybrid yeast Zygosaccharomyces parabailii', Applied and Environmental Microbiology, 84(5), e02294-17 (17pp). DOI: 10.1128/aem.02294-17	en
dc.identifier.doi	10.1128/aem.02294-17
dc.identifier.endpage	17
dc.identifier.issn	0099-2240
dc.identifier.issued	5
dc.identifier.journaltitle	Applied and Environmental Microbiology	en
dc.identifier.startpage	1
dc.identifier.uri	https://hdl.handle.net/10468/5487
dc.identifier.volume	84
dc.language.iso	en	en
dc.publisher	American Society for Microbiology	en
dc.relation.project	info:eu-repo/grantAgreement/EC/FP7::SP3::PEOPLE/606795/EU/Yeast Cell Factories: Training Researchers to Apply Modern Post-Genomic Methods In Yeast Biotechnology/YEASTCELL	en
dc.relation.uri	http://aem.asm.org/content/early/2017/12/18/AEM.02294-17.abstract
dc.rights	© 2017 Ortiz-Merino et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.	en
dc.rights.uri	https://creativecommons.org/licenses/by/4.0/	en
dc.subject	Zygosaccharomyces parabailii	en
dc.subject	Hybrid yeast	en
dc.subject	Lactic acid stress	en
dc.title	Transcriptional response to lactic acid stress in the hybrid yeast Zygosaccharomyces parabailii	en
dc.type	Article (peer-reviewed)	en

Transcriptional response to lactic acid stress in the hybrid yeast Zygosaccharomyces parabailii

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