title: Gene expression and biochemical analysis of cheese-ripening yeasts: focus on catabolism of L-methionine, lactate, and lactose.
abstract: DNA microarrays of 86 genes from the yeasts Debaryomyces hansenii, Kluyveromyces marxianus, and Yarrowia lipolytica were developed to determine which genes were expressed in a medium mimicking a cheese-ripening environment. These genes were selected for potential involvement in lactose/lactate catabolism and the biosynthesis of sulfur-flavored compounds. Hybridization conditions to follow specifically the expression of homologous genes belonging to different species were set up. The microarray was first validated on pure cultures of each yeast; no interspecies cross-hybridization was observed. Expression patterns of targeted genes were studied in pure cultures of each yeast, as well as in coculture, and compared to biochemical data. As expected, a high expression of the LAC genes of K. marxianus was observed. This is a yeast that efficiently degrades lactose. Several lactate dehydrogenase-encoding genes were also expressed essentially in D. hansenii and K. marxianus, which are two efficient deacidifying yeasts in cheese ripening. A set of genes possibly involved in l-methionine catabolism was also used on the array. Y. lipolytica, which efficiently assimilates l-methionine, also exhibited a high expression of the Saccharomyces cerevisiae orthologs BAT2 and ARO8, which are involved in the l-methionine degradation pathway. Our data provide the first evidence that the use of a multispecies microarray could be a powerful tool to investigate targeted metabolism and possible metabolic interactions between species within microbial cocultures.
authors.affiliation: UMR 782 Génie et Microbiologie des Procédés Alimentaires, INRA, F-78850 Thiverval-Grignon, France.
authors.forename: Orianne
authors.initials: O
authors.lastname: Cholet
authors.forename: Alain
authors.initials: A
authors.lastname: Hénaut
authors.forename: Serge
authors.initials: S
authors.lastname: Casaregola
authors.forename: Pascal
authors.initials: P
authors.lastname: Bonnarme
mesh_terms: D002611:Cheese / Q000382:microbiology; D015169:Colony Count, Microbial; D005516:Food Microbiology; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D007716:Kluyveromyces / Q000235:genetics / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000235:genetics; D007763:Lac Operon; D019344:Lactic Acid / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D004718:Saccharomycetales / Q000235:genetics / Q000378:metabolism; D000637:Transaminases / Q000235:genetics; D025062:Yarrowia / Q000235:genetics / Q000378:metabolism; D015003:Yeasts / Q000235:genetics / Q000378:metabolism*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D019344:Lactic Acid; D008715:Methionine; D007770:L-Lactate Dehydrogenase; D000637:Transaminases; C101127:BAT2 protein, S cerevisiae; D007785:Lactose