Bartle, L.Peltier, E.Sundstrom, J.F.Sumby, K.Mitchell, J.G.Jiranek, V.Marullo, P.2021-07-072021-07-072021Applied Microbiology and Biotechnology, 2021; 105(12):5053-50660175-75981432-0614http://hdl.handle.net/2440/131090The two most commonly used wine microorganisms, Saccharomyces cerevisiae yeast and Oenococcus oeni bacteria, are responsible for completion of alcoholic and malolactic fermentation (MLF), respectively. For successful co-inoculation, S. cerevisiae and O. oeni must be able to complete fermentation; however, this relies on compatibility between yeast and bacterial strains. For the first time, quantitative trait loci (QTL) analysis was used to elucidate whether S. cerevisiae genetic makeup can play a role in the ability of O. oeni to complete MLF. Assessment of 67 progeny from a hybrid S. cerevisiae strain (SBxGN), co-inoculated with a single O. oeni strain, SB3, revealed a major QTL linked to MLF completion by O. oeni. This QTL encompassed a well-known translocation, XV-t-XVI, that results in increased SSU1 expression and is functionally linked with numerous phenotypes including lag phase duration and sulphite export and production. A reciprocal hemizygosity assay was performed to elucidate the effect of the gene SSU1 in the SBxGN background. Our results revealed a strong effect of SSU1 haploinsufficiency on O. oeni’s ability to complete malolactic fermentation during co-inoculation and pave the way for the implementation of QTL mapping projects for deciphering the genetic bases of microbial interactions.en© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021Yeast-bacteria interactions; malolactic fermentation; QTL; wine; SSU1Journal article100004221810.1007/s00253-021-11376-x0006594138000042-s2.0-85107502789578261Bartle, L. [0000-0001-7112-1801]Sundstrom, J.F. [0000-0002-4898-3101]Sumby, K. [0000-0002-1833-2025]Jiranek, V. [0000-0002-9775-8963]