Metabolomic Comparison of Saccharomyces cerevisiae and the Cryotolerant Species S. bayanus var. uvarum and S. kudriavzevii during Wine Fermentation at Low Temperature

Temperature is one of the most important parameters affecting the length and rate of alcoholic fermentation and final wine quality. Wine produced at low temperature is often considered to have improved sensory qualities. However, there are certain drawbacks to low temperature fermentations such as reduced growth rate, long lag phase, and sluggish or stuck fermentations. To investigate the effects of temperature on commercial wine yeast, we compared its metabolome growing at 12°C and 28°C in a synthetic must. Some species of the Saccharomyces genus have shown better adaptation at low temperature than Saccharomyces cerevisiae. This is the case of the cryotolerant yeasts Saccharomyces bayanus var. uvarum and Saccharomyces kudriavzevii. In an attempt to detect inter-specific metabolic differences, we characterized the metabolome of these species growing at 12°C, which we compared with the metabolome of S. cerevisiae (not well adapted at low temperature) at the same temperature. Our results show that the main differences between the metabolic profiling of S. cerevisiae growing at 12°C and 28°C were observed in lipid metabolism and redox homeostasis. Moreover, the global metabolic comparison among the three species revealed that the main differences between the two cryotolerant species and S. cerevisiae were in carbohydrate metabolism, mainly fructose metabolism. However, these two species have developed different strategies for cold resistance. S. bayanus var. uvarum presented elevated shikimate pathway activity, while S. kudriavzevii displayed increased NAD⁺ synthesis.     

Sunscreen Products as Emerging Pollutants to Coastal Waters

A growing awareness of the risks associated with skin exposure to ultraviolet (UV) radiation over the past decades has led to increased use of sunscreen cosmetic products leading the introduction of new chemical compounds in the marine environment. Although coastal tourism and recreation are the largest and most rapidly growing activities in the world, the evaluation of sunscreen as source of chemicals to the coastal marine system has not been addressed. Concentrations of chemical UV filters included in the formulation of sunscreens, such as benzophehone 3 (BZ-3), 4-methylbenzylidene camphor (4-MBC), TiO₂ and ZnO, are detected in nearshore waters with variable concentrations along the day and mainly concentrated in the surface microlayer (i.e. 53.6–577.5 ng L^-1 BZ-3; 51.4–113.4 ng L^-1 4-MBC; 6.9–37.6 µg L^-1 Ti; 1.0–3.3 µg L^-1 Zn). The presence of these compounds in seawater suggests relevant effects on phytoplankton. Indeed, we provide evidences of the negative effect of sunblocks on the growth of the commonly found marine diatom Chaetoceros gracilis (mean EC₅₀ = 125±71 mg L^-1). Dissolution of sunscreens in seawater also releases inorganic nutrients (N, P and Si forms) that can fuel algal growth. In particular, PO₄ ³⁻ is released by these products in notable amounts (up to 17 µmol PO₄ ³⁻ g⁻¹). We conservatively estimate an increase of up to 100% background PO₄ ³⁻ concentrations (0.12 µmol L^-1 over a background level of 0.06 µmol L^-1) in nearshore waters during low water renewal conditions in a populated beach in Majorca island. Our results show that sunscreen products are a significant source of organic and inorganic chemicals that reach the sea with potential ecological consequences on the coastal marine ecosystem.     

Early anther ablation triggers parthenocarpic fruit development in tomato

Fruit set and fruit development in tomato is largely affected by changes in environmental conditions, therefore autonomous fruit set independent of fertilization is a highly desirable trait in tomato. Here, we report the production and characterization of male‐sterile transgenic plants that produce parthenocarpic fruits in two tomato cultivars (Micro‐Tom and Moneymaker). We generated male‐sterility using the cytotoxic gene barnase targeted to the anthers with the PsEND1 anther‐specific promoter. The ovaries of these plants grew in the absence of fertilization producing seedless, parthenocarpic fruits. Early anther ablation is essential to trigger the developing of the transgenic ovaries into fruits, in the absence of the signals usually generated during pollination and fertilization. Ovaries are fully functional and can be manually pollinated to obtain seeds. The transgenic plants obtained in the commercial cultivar Moneymaker show that the parthenocarpic development of the fruit does not have negative consequences in fruit quality. Throughout metabolomic analyses of the tomato fruits, we have identified two elite lines which showed increased levels of several health promoting metabolites and volatile compounds. Thus, early anther ablation can be considered a useful tool to promote fruit set and to obtain seedless and good quality fruits in tomato plants. These plants are also useful parental lines to be used in hybrid breeding approaches.     

Spatio‐temporal patterns and interactions with honeydew‐producing Hemiptera of ants in a Mediterranean citrus orchard

• 1 The role of ants in the citrus agro‐ecosystem is controversial and understanding their ecology may help to clarify their function. The present study determined the daily and seasonal foraging patterns, the spatial distribution, the feeding sources and the associations with honeydew‐producing Hemiptera of three ant species that forage in citrus canopies.
• 2 The dominant ants Pheidole pallidula (Nylander) (Myrmicinae) and Lasius grandis Forel (Formicinae) foraged in mutually exclusive territories within the field, although they both shared their territory with the subordinate Plagiolepis schmitzii Forel (Formicinae), a distribution pattern known as ‘ant mosaic’.
• 3 The observed mean overlap for the spatial distribution was significantly lower than the generated by null models, providing strong evidence of spatial interspecific competition, especially between the two dominants.
• 4 Ants ascended to the canopies from April until November. Colony nutritional requirements and temperature probably shape their seasonal foraging patterns. The daily activity pattern of P. schmitzii was strictly diurnal, whereas L. grandis and P. pallidula were active during the entire day.
• 5 The ants' diet in the canopies consisted principally of hemipteran honeydew, whereas citrus nectar and predation/scavenging did not represent important food sources. More than 60% of the total honeydew sources and 100% of the citrus mealybug Planococcus citri colonies were tended by ants during spring and summer.

     

Potassium and sodium uptake systems in fungi. The transporter diversity of Magnaporthe oryzae

In this study, we report an inventory of the K(+) uptake systems in 62 fungal species for which the complete genome sequences are available. This inventory reveals that three types of K(+) uptake systems, TRK and HAK transporters and ACU ATPases, are widely present in several combinations across fungal species. PAT ATPases are less frequently present and are exceptional in Ascomycota. The genome of Magnaporthe oryzae contains four TRK, one HAK, and two ACU genes. The study of the expression of these genes at high K(+), K(+) starvation, and in infected rice leaves revealed that the expression of four genes, ACU1, ACU2, HAK1, and TRK1 is much lower than that of TRK2, TRK3, and TRK4, except under K(+) starvation. The two ACU ATPases were cloned and functionally identified as high-affinity K(+) or Na(+) uptake systems. These two ATPases endow Saccharomyces cerevisiae with the capacity to grow for several generations in low Na(+) concentrations when K(+) was absent, which produces a dramatic increase of cellular Na(+)/K(+) ratio.     

Comparing latitudinal and upstream–downstream gradients: life history traits of invasive mosquitofish

Aim Variation of life history traits along spatial gradients is poorly understood in invasive species and particularly in freshwater fish. We aimed to examine life history variation in a highly invasive fish (Gambusia holbrooki) along latitudinal and upstream–downstream river gradients and to assess the effects of age on this variation. We hypothesized similar responses in populations inhabiting environments more favourable to this species (lower latitudes and lower reaches of rivers). Location European rivers from southern Spain to southern France. Methods We sampled mosquitofish from the lowest reaches of ten river basins along 6° of latitude in the Mediterranean region and seven sites along the upstream–downstream gradient in three of the rivers. We examined abundance, population structure, size‐at‐age and other life history traits along these gradients. Results As hypothesized, lower reaches and lower latitudes both resulted in higher reproductive effort and lower body condition of mosquitofish. However, these patterns explained low per cent variation, were nonlinear and strongly depended on fish age. Independently of fish size, age groups differed in reproductive effort, in the gonadal weight–size relationship and its variation along spatial gradients. Mean size‐at‐age (or overall body size) did not vary with latitude (so the intra‐specific version of Bergmann’s rule or its converse does not apply) and in contrast increased upstream in rivers. Main conclusions Our findings suggest that for life history traits of freshwater organisms, river longitudinal variation plays a role as important as climate, with often differential effects. Our results also illustrate the poor knowledge of spatial variation of many life history traits, which precludes the understanding and prediction of biological invasions in a rapidly changing world.     

Study of plants visited by honeybees (Apis mellifera L.) in the Central Rif Region (N. Morocco) using pollen analysis

Quantitative pollen analyses of Moroccan honey samples provided by amateur beekeepers from the Central Rif region demonstrates that nectar is generally the main honey source, and that most honeys have a medium‐low presence of botanical elements. However, two samples reached values as high as 1.08–1.83 qualifying as honeydew honeys. Qualitative results yielded 60 pollen types belonging to 33 families. Ammi visnaga L., Mentha pulegium L., M. rotundifolia (L.) Hudson, Eucalyptus camaldulensis Dehnh. and Rubus ulmifolius Schott. were the main nectar sources, and Cistaceae, Poaceae, Cannabis sativa L. and grasses were exploited as a pollen source. When compared to the parent vegetation honeydew and mint sources are widely exploited, but other sources such as eucalyptus and heather are underutilised.     

Drought and cadmium may be as effective as salinity in conferring subsequent salt stress tolerance in Cakile maritima

Plants are often exposed to a combination of stresses, which can occur simultaneously or at different times throughout their life. In this study, the effects of salinity, drought and cadmium pre-treatments were evaluated on the subsequent response of Cakile maritima, a halophytic species, to various levels of salinity (from 100 to 800 mM NaCl) after a recovery time of 2 weeks. Studies were performed in two sets of experiments in a glasshouse under short and long photoperiod (November and July, respectively). In both experiments and in contrast to control plants (not exposed to any previous stress), plants previously exposed to drought, salt or cadmium stress showed lower levels of hydrogen peroxide and malondialdehyde, an indicator of lipid peroxidation, upon salt treatment, particularly at high NaCl concentrations. Oxidative stress alleviation was not only observed at 800 mM NaCl under short photoperiod, but also at 600 and 800 mM NaCl under long photoperiod in terms of reduced salt-induced increases in hydrogen peroxide and malondialdehyde levels in plants previously exposed to drought, salt or cadmium stress. Previous exposure of plants to all stresses additionally caused decreased levels of jasmonic acid, which might be associated with a lower oxidative stress, differences being observed again at 800 mM NaCl only under short photoperiod and at 600 and 800 mM NaCl under long photoperiod. In conclusion, a relatively long-term stress memory was found in C. maritima pre-exposed to salinity, drought or cadmium, which resulted in a lower oxidative stress when subsequently exposed to salinity. The positive effects of drought and cadmium were of similar magnitude to those provided by salt pre-exposure, which indicated an effective cross-tolerance response in this species.     

Morpho-physiological variations in response to NaCl stress during vegetative and reproductive development of rice

The complex nature of plant resistance to adverse environmental conditions, such as salinity and drought requires a better understanding of the stress-induced changes that may be involved in tolerance mechanisms. Here we investigate stress-related morpho-physiological effects during vegetative and reproductive growth in two Japonica rice cultivars (Bomba and Bahia) exposed to a range of NaCl concentrations from the seedling stage. The stress-related detrimental effects were observed either earlier or to a higher extent in cv. Bomba than in Bahia. Damages to the photosynthetic apparatus were related to loss of chlorophyll (Chl) and to a decrease of the maximum potential efficiency of PSII (F _v /F _m), affecting negatively net CO₂ assimilation rate (P _N). Stress-related leaf anatomical alterations were analysed during the vegetative and reproductive stages. The size of bulliform cells as well as dimensions related to the vascular system increased under mild stress but decreased in the longer term or under higher stress level. The pattern of the anatomical alterations observed at the reproductive stage under 20 mM NaCl was reflected in poor panicle development and yield loss, with effects more pronounced in cv. Bomba than in Bahia. In summary, our results show that some physiological and, particularly, leaf anatomical responses induced by NaCl stress are distinctive indicators of sensitivity to salt stress in rice cultivars.     

Genetic structure,relationships and admixture with wild relatives in native pig breeds from Iberia and its islands

Background

Native pig breeds in the Iberian Peninsula are broadly classified as belonging to either the Celtic or the Mediterranean breed groups, but there are other local populations that do not fit into any of these groups. Most of the native pig breeds in Iberia are in danger of extinction, and the assessment of their genetic diversity and population structure, relationships and possible admixture between breeds, and the appraisal of conservation alternatives are crucial to adopt appropriate management strategies.

Methods

A panel of 24 microsatellite markers was used to genotype 844 animals representing the 17 most important native swine breeds and wild populations existing in Portugal and Spain and various statistical tools were applied to analyze the results.

Results

Genetic diversity was high in the breeds studied, with an overall mean of 13.6 alleles per locus and an average expected heterozygosity of 0.80. Signs of genetic bottlenecks were observed in breeds with a small census size, and population substructure was present in some of the breeds with larger census sizes. Variability among breeds accounted for about 20% of the total genetic diversity, and was explained mostly by differences among the Celtic, Mediterranean and Basque breed groups, rather than by differences between domestic and wild pigs. Breeds clustered closely according to group, and proximity was detected between wild pigs and the Mediterranean cluster of breeds. Most breeds had their own structure and identity, with very little evidence of admixture, except for the Retinto and Entrepelado varieties of the Mediterranean group, which are very similar. Genetic influence of the identified breed clusters extends beyond the specific geographical areas across borders throughout the Iberian Peninsula, with a very sharp transition from one breed group to another. Analysis of conservation priorities confirms that the ranking of a breed for conservation depends on the emphasis placed on its contribution to the between- and within-breed components of genetic diversity.

Conclusions

Native pig breeds in Iberia reveal high levels of genetic diversity, a solid breed structure and a clear organization in well-defined clusters.