title: Early transcriptional response to biotic stress in mixed starter fermentations involving Saccharomyces cerevisiae and Torulaspora delbrueckii.
abstract: Advances in microbial wine biotechnology have led to the recent commercialization of several non-Saccharomyces starter cultures. These are intended to be used in either simultaneous or sequential inoculation with Saccharomyces cerevisiae. The different types of microbial interactions that can be stablished during wine fermentation acquire an increased relevance in the context of these mixed-starter fermentations. We analysed the transcriptional response to co-cultivation of S. cerevisiae and Torulaspora delbrueckii. The study focused in the initial stages of wine fermentation, before S. cerevisiae completely dominates the mixed cultures. Both species showed a clear response to the presence of each other, even though the portion of the genome showing altered transcription levels was relatively small. Changes in the transcription pattern suggested a stimulation of metabolic activity and growth, as a consequence of the presence of competitors in the same medium. The response of S. cerevisiae seems to take place earlier, as compared to T. delbrueckii. Enhanced glycolytic activity of the mixed culture was confirmed by the CO2production profile during these early stages of fermentation. Interestingly, HSP12 expression appeared induced by co-cultivation for both of S. cerevisiae and Torulaspora delbrueckii in the two time points studied. This might be related with a recently described role of Hsp12 in intercellular communication in yeast. Expression of S. cerevisiae PAU genes was also stimulated in mixed cultures.
authors.affiliation: Instituto de Ciencias de la Vid y del Vino (CSIC-Universidad de la Rioja-Gobierno de La Rioja), Logroño, La Rioja, Spain. Electronic address: jordi.tronchoni@icvv.es.
authors.forename: Jordi
authors.initials: J
authors.lastname: Tronchoni
authors.affiliation: Instituto de Ciencias de la Vid y del Vino (CSIC-Universidad de la Rioja-Gobierno de La Rioja), Logroño, La Rioja, Spain. Electronic address: jantonio.curiel@icvv.es.
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Curiel
authors.affiliation: Instituto de Ciencias de la Vid y del Vino (CSIC-Universidad de la Rioja-Gobierno de La Rioja), Logroño, La Rioja, Spain. Electronic address: pilar.morales@icvv.es.
authors.forename: Pilar
authors.initials: P
authors.lastname: Morales
authors.affiliation: Instituto de Ciencias de la Vid y del Vino (CSIC-Universidad de la Rioja-Gobierno de La Rioja), Logroño, La Rioja, Spain. Electronic address: rafael.torres@icvv.es.
authors.forename: Rafael
authors.initials: R
authors.lastname: Torres-Pérez
authors.affiliation: Instituto de Ciencias de la Vid y del Vino (CSIC-Universidad de la Rioja-Gobierno de La Rioja), Logroño, La Rioja, Spain. Electronic address: ramon.gonzalez@icvv.es.
authors.forename: Ramon
authors.initials: R
authors.lastname: Gonzalez
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry; D018920:Coculture Techniques; D005285:Fermentation; D005516:Food Microbiology; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D006019:Glycolysis; D006360:Heat-Shock Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry; D017423:Sequence Analysis, RNA; D013045:Species Specificity; D055319:Torulaspora / Q000378:metabolism*; D014158:Transcription, Genetic; D059467:Transcriptome; D014920:Wine / Q000032:analysis* / Q000382:microbiology*; D015002:Yeast, Dried / Q000378:metabolism
chemical_list: C112591:HSP12 protein, S cerevisiae; D006360:Heat-Shock Proteins; D029701:Saccharomyces cerevisiae Proteins; D002245:Carbon Dioxide
keywords: Biotic stress; Interspecific interaction; Mixed starter; Non-Saccharomyces; Wine fermentation