TY - JOUR
T1 - Phenotype-independent isolation of interspecies Saccharomyces hybrids by dual-dye fluorescent staining and fluorescence-activated cell sorting
AU - Gorter De Vries, Arthur R.
AU - Koster, Charlotte C.
AU - Weening, Susan M.
AU - Luttik, Marijke A.H.
AU - Kuijpers, Niels G.A.
AU - Geertman, Jan Maarten A.
AU - Pronk, Jack T.
AU - Daran, Jean Marc G.
PY - 2019
Y1 - 2019
N2 - Interspecies hybrids of Saccharomyces species are found in a variety of industrial environments and often outperform their parental strains in industrial fermentation processes. Interspecies hybridization is therefore increasingly considered as an approach for improvement and diversification of yeast strains for industrial application. However, current hybridization methods are limited by their reliance on preexisting or introduced selectable phenotypes. This study presents a high-throughput phenotype-independent method for isolation of interspecies Saccharomyces hybrids based on dual dye-staining and subsequent mating of two strains, followed by enrichment of double-stained hybrid cells from a mating population by fluorescence-activated cell sorting (FACS). Pilot experiments on intra-species mating of heterothallic haploid S. cerevisiae strains showed that 80% of sorted double-stained cells were hybrids. The protocol was further optimized by mating an S. cerevisiae haploid with homothallic S. eubayanus spores with complementary selectable phenotypes. In crosses without selectable phenotype, using S. cerevisiae and S. eubayanus haploids derived from laboratory as well as industrial strains, 10 to 15% of double-stained cells isolated by FACS were hybrids. When applied to rare mating, sorting of double-stained cells consistently resulted in about 600-fold enrichment of hybrid cells. Mating of dual-stained cells and FACS-based selection allows efficient enrichment of interspecies Saccharomyces hybrids within a matter of days and without requiring selectable hybrid phenotypes, both for homothallic and heterothallic strains. This strategy should accelerate the isolation of laboratory-made hybrids, facilitate research into hybrid heterosis and offer new opportunities for non-GM industrial strain improvement and diversification.
AB - Interspecies hybrids of Saccharomyces species are found in a variety of industrial environments and often outperform their parental strains in industrial fermentation processes. Interspecies hybridization is therefore increasingly considered as an approach for improvement and diversification of yeast strains for industrial application. However, current hybridization methods are limited by their reliance on preexisting or introduced selectable phenotypes. This study presents a high-throughput phenotype-independent method for isolation of interspecies Saccharomyces hybrids based on dual dye-staining and subsequent mating of two strains, followed by enrichment of double-stained hybrid cells from a mating population by fluorescence-activated cell sorting (FACS). Pilot experiments on intra-species mating of heterothallic haploid S. cerevisiae strains showed that 80% of sorted double-stained cells were hybrids. The protocol was further optimized by mating an S. cerevisiae haploid with homothallic S. eubayanus spores with complementary selectable phenotypes. In crosses without selectable phenotype, using S. cerevisiae and S. eubayanus haploids derived from laboratory as well as industrial strains, 10 to 15% of double-stained cells isolated by FACS were hybrids. When applied to rare mating, sorting of double-stained cells consistently resulted in about 600-fold enrichment of hybrid cells. Mating of dual-stained cells and FACS-based selection allows efficient enrichment of interspecies Saccharomyces hybrids within a matter of days and without requiring selectable hybrid phenotypes, both for homothallic and heterothallic strains. This strategy should accelerate the isolation of laboratory-made hybrids, facilitate research into hybrid heterosis and offer new opportunities for non-GM industrial strain improvement and diversification.
KW - FACS
KW - Heterosis
KW - Lager beer brewing
KW - Marker-free mating
KW - Non-GMO
KW - Saccharomyces eubayanus × Saccharomyces cerevisiae hybrids
UR - http://www.scopus.com/inward/record.url?scp=85068127985&partnerID=8YFLogxK
U2 - 10.3389/fmicb.2019.00871
DO - 10.3389/fmicb.2019.00871
M3 - Article
SN - 1664-302X
VL - 10
JO - Frontiers in Microbiology
JF - Frontiers in Microbiology
IS - APR
M1 - 871
ER -