Zygosaccharomyces rouxii is a fructophilic yeast that consumes fructose preferably to glucose. This behavior seems to be related to sugar uptake. In this study, we constructed Z. rouxii single-, double-, and triple-deletion mutants in the UL4 strain background (a ura3 strain derived from CBS 732 T ) by deleting the genes encoding the specific fructose facilitator Z. rouxii Ffz1 (ZrFfz1), the fructose/glucose facilitator ZrFfz2, and/or the fructose symporter ZrFsy1. We analyzed the effects on the growth phenotype, on kinetic parameters of fructose and glucose uptake, and on sugar consumption profiles. No growth phenotype was observed on fructose or glucose upon deletion of FFZ genes. Deletion of ZrFFZ1 drastically reduced fructose transport capacity, increased glucose transport capacity, and eliminated the fructophilic character, while deletion of ZrFFZ2 had almost no effect. The strain in which both FFZ genes were deleted presented even higher consumption of glucose than strain Zrffz1⌬, probably due to a reduced repressing effect of fructose. This study confirms the molecular basis of the Z. rouxii fructophilic character, demonstrating that ZrFfz1 is essential for Z. rouxii fructophilic behavior. The gene is a good candidate to improve the fructose fermentation performance of industrial Saccharomyces cerevisiae strains.T he most problematic spoilage yeasts in the food and beverage industry belong to the genus Zygosaccharomyces. Zygosaccharomyces bailii and Zygosaccharomyces rouxii are the main spoilage yeasts of sugar syrups, fruit juices, honey, and sweet sauces, due to their unique properties, such as high resistance to weak-acid preservatives, extreme osmotolerance (some Z. rouxii strains are able to grow on 90% [wt/vol] glucose), ability to vigorously ferment hexoses (which can cause swelling or bursting of packaging, due to gas accumulation), ability to adapt to high temperatures, and growth at low pH (1, 2). Z. rouxii is also industrially used in the fermentation of some salted condiments, such as soy sauce and miso paste, and in the production of balsamic vinegar (3, 4).Z. rouxii and Z. bailii are fructophilic yeasts, meaning that they consume fructose faster than glucose, a behavior opposite to that of the glucophilic Saccharomyces cerevisiae, which prefers glucose over fructose (5). In 1956, Sols (6) showed that phosphorylation of sugars was not involved in fructophily of a "sauternes yeast" (probably Z. bailii [7]), suggesting that another step preceding phosphorylation was the main regulator of the fructophilic behavior. This was further supported by later studies that indicated that hexokinase activities were similar in Z. bailii and S. cerevisiae and that sugar transport should be involved in Z. bailii fructophily (5).The transport across the plasma membrane is the first step at which the utilization of nutrients by cells can be controlled and regulated in response to extracellular conditions and intracellular requirements. The majority of sugar transporters belong to the sugar porter (SP) family, t...

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Fructophily has been described in yeasts as the ability to utilize fructose preferentially when fructose and glucose are available in the environment. In Zygosaccharomyces bailii and Zygosaccharomyces rouxii, fructophilic behaviour has been associated with the presence of a particular type of high-capacity and low-affinity fructose transporters designated Ffz. In this study, a PCR screening was performed in several yeasts using degenerate primers suitable to detect FFZ-like genes. In parallel, fructophilic character was evaluated in the same strains by comparing the relative consumption rate of fructose and glucose. For all the strains in which FFZ-like genes were detected, fructophilic behaviour was observed (25 strains). Results show that FFZ genes are ubiquitous in the Zygosaccharomyces and Starmerella clades. Strains of Lachancea fermentati, Torulaspora microellipsoides and Zygotorulaspora florentina were not fructophilic and did not harbour FFZ genes. It is of note that these new species were recently removed by taxonomists from the Zygosaccharomyces clade, supporting the view that the presence of FFZ-like genes is a main characteristic of Zygosaccharomyces. Among the strains tested, only Hanseniaspora guilliermondii NCYC2380 was an exception, having a preference for fructose in medium with high sugar concentrations, despite no FFZ-like genes being detected in the screening. Furthermore, this study supports the previous idea of the emergence of a new family of hexose transporters (Ffz facilitators) distinct from the Sugar Porter family.

Knowledge mobilisation is required to "bridge the gap" between research, policy and practice. This activity is dependent on the amount, richness and quality of the data published. To understand the impact of a changing climate on commercial species, stakeholder communities require better knowledge of their past and current situations. The common cockle (Cerastoderma edule) is an excellent model species for this type of analysis, as it is well-studied due to its cultural, commercial and ecological significance in west Europe. Recently, C. edule harvests have decreased, coinciding with frequent mass mortalities, due to factors such as a changing climate and diseases. In this study, macro and micro level marine historical ecology techniques were used to create datasets on topics including: cockle abundance, spawning duration and harvest levels, as well as the ecological factors impacting those cockle populations. These data were correlated with changing climate and the Atlantic Multidecadal Oscillation (AMO) index to assess if they are drivers of cockle abundance and harvesting. The analyses identified the key stakeholder communities involved in cockle research and data acquisition. It highlighted that data collection was sporadic and lacking in cross-national/stakeholder community coordination. A major finding was that local variability in cockle populations is influenced by biotic (parasites) and abiotic (temperature, legislation and harvesting) factors, and at a global scale by climate (AMO Index). This comprehensive study provided an insight into the European cockle fishery but also highlights the need to identify the type of data required, the importance of standardised monitoring, and dissemination efforts, taking into account the knowledge, source, and audience. These factors are key elements that will be highly beneficial not only to the cockle stakeholder communities but to other commercial species.

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