Yeast diversity in open agave fermentations across Mexico.

Yeasts are a diverse group of fungal microorganisms that are widely used to produce fermented foods and beverages. In Mexico, open fermentations are used to obtain spirits from agave plants. Despite the prevalence of this traditional practice throughout the country, yeasts have only been isolated and studied from a limited number of distilleries. To systematically describe the diversity of yeast species from open agave fermentations, here we generate the YMX-1.0 culture collection by isolating 4524 strains from 68 sites with diverse climatic, geographical, and biological contexts. We used MALDI-TOF mass spectrometry for taxonomic classification and validated a subset of the strains by ITS and D1/D2 sequencing, which also revealed two potential novel species of Saccharomycetales. Overall, the composition of yeast communities was weakly associated with local variables and types of climate, yet a core set of six species was consistently isolated from most producing regions. To explore the intraspecific variation of the yeasts from agave fermentations, we sequenced the genomes of four isolates of the nonconventional yeast Kazachstania humilis. The genomes of these four strains were substantially distinct from a European isolate of the same species, suggesting that they may belong to different populations. Our work contributes to the understanding and conservation of an open fermentation system of great cultural and economic importance, providing a valuable resource to study the biology and genetic diversity of microorganisms living at the interface of natural and human-associated environments.

Assessment of different temporary immersion systems in the micropropagation of anthurium (Anthurium andreanum).

Anthurium has been micropropagated mainly through conventional techniques in semisolid culture medium. However, this culture system involves constraints due to the low number of shoots produced and the high costs of the gelling agent and labor. Temporary immersion systems (TIS) are an alternative for increasing biological performance, reducing costs, and facilitating a semi-automated micropropagation process. The objective of this study was to compare the efficiency of different types of TIS during the in vitro propagation of anthurium. We used 2-cm-long nodal segments from in vitro plants. Explants were cultured in different TIS: temporary immersion bioreactors (TIB®), Ebb-and-Flow bioreactor, and recipient for automated temporary immersion (RITA®), with a 2-min immersion frequency at 12-h intervals. We used Murashige and Skoog (MS) medium supplemented with 3% (w/v) of sucrose and 8.88 µM benzylaminopurine. After 60 days of culture, we evaluated various physiological variables and the percent survival in the different TIS. The largest numbers of shoots per explant were observed in TIB® and Ebb-and-Flow, with 50.83 and 43.16 shoots per explant, respectively; the lowest number of shoots per explant was observed in RITA®, with 30.66. TIB® yielded the highest content of photosynthetic pigments (chlorophyll a, b, and total chlorophyll), stomatal index, and percentage of closed stomata relative to both Ebb-and-Flow and RITA®. The TIB® and RITA® systems showed a 99% shoot survival, while Ebb-and-Flow yielded 86% survival. In conclusion, TIS design and type affect a number of physiological processes and in vitro development, with TIB® as a feasible option for the commercial micropropagation of anthurium.