Survival of respiratory viral pathogens in expelled saliva microdroplets is central to their transmission, yet the factors that determine survival in such microdroplets are not well understood. Here we combine microscopy imaging with virus viability assays to study survival of three bacteriophages suggested as good models for respiratory pathogens: the enveloped Phi6 (a surrogate for SARS-CoV-2), and the non-enveloped PhiX174 and MS2. We measured virus viability in human saliva microdroplets, SM buffer, and water following deposition on glass surfaces at various relative humidities (RH). Saliva and water microdroplets dried out rapidly, within minutes, at all tested RH levels (23%, 43%, 57%, and 78%), while SM microdroplets remained hydrated at RH >= 57%. Generally, the survival of all three viruses in dry saliva microdroplets was significantly greater than those in SM buffer and water under all RH (except PhiX174 in water under 57% RH survived the best among 3 media). Thus, atmosphere RH and microdroplet hydration state are not sufficient to explain virus survival, indicating that the virus-suspended medium, and association with saliva components in particular, likely play a role in virus survival. Uncovering the exact properties and components that make saliva a favorable environment for the survival of viruses, in particular enveloped ones like Phi6, is thus of great importance for reducing transmission of viral respiratory pathogens including SARS-CoV-2.

Coral associated fungi are widespread, highly diverse and are part and parcel of the coral holobiont. To study how environmental conditions prevailing near the coral-host may affect fungal diversity, the culturable (isolated on potato dextrose agar) mycobiome associated with Acropora loripes colonies was seasonally sampled along a depth gradient in the Gulf of Aqaba. Fragments were sampled from both apparently healthy coral colonies as well as those exhibiting observable lesions. Based on phylogenetic analysis of 197 fungal sequences, Ascomycota were the most prevalent (91.9%). The abundance of fungi increased with increasing water depth, where corals sampled at 25 m yielded up to 70% more fungal colony forming units (CFUs) than those isolated at 6 m. Fungal diversity at 25 m was also markedly higher, with over 2-fold more fungal families represented. Diversity was also higher in lesioned coral samples, when compared to apparently healthy colonies. In winter, concurrent with water column mixing and increased levels of available nutrients, at the shallow depths, Saccharomytacea and Sporidiobolacea were more prevalent, while in spring and fall Trichocomacea (overall, the most prevalent family isolated throughout this study) were the most abundant taxa isolated at these depths as well as at deeper sampling sites. Our results highlight the dynamic nature of the culturable coral mycobiome and its sensitivity to environmental conditions and coral health.

Species of Didymellaceae have a cosmopolitan distribution and are geographically widespread, occurring in diverse ecosystems. The family includes several important plant pathogenic fungi associated with fruit, leaf, stem and root diseases on a wide variety of hosts, as well as endophytic, saprobic and clinically relevant species. The Didymellaceae was recently revised based on morphological and phylogenetic analyses of ex-type strains subjected to DNA sequencing of partial gene data of the LSU, ITS, rpb2 and tub2 loci. Several poly- and paraphyletic genera, including Ascochyta, Didymella and Phoma were redefined, along with the introduction of new genera. In the present study, a global collection of 1 124 Didymellaceae strains from 92 countries, 121 plant families and 55 other substrates, including air, coral, human tissues, house dust, fungi, insects, soil, and water were examined via multi-locus phylogenetic analyses and detailed morphological comparisons, representing the broadest sampling of Didymellaceae to date. Among these, 97 isolates representing seven new genera, 40 new species and 21 new combinations were newly introduced in Didymellaceae. In addition, six epitypes and six neotypes were designated to stabilise the taxonomy and use of older names. A robust, multi-locus reference phylogenetic tree of Didymellaceae was generated. In addition, rpb2 was revealed as the most effective locus for the identification of Didymellaceae at species level, and is proposed as a secondary DNA marker for the family.

Fungi have the ability to transform organic materials into a rich and diverse set of useful products and provide distinct opportunities for tackling the urgent challenges before all humans. Fungal biotechnology can advance the transition from our petroleum-based economy into a bio-based circular economy and has the ability to sustainably produce resilient sources of food, feed, chemicals, fuels, textiles, and materials for construction, automotive and transportation industries, for furniture and beyond. Fungal biotechnology offers solutions for securing, stabilizing and enhancing the food supply for a growing human population, while simultaneously lowering greenhouse gas emissions. Fungal biotechnology has, thus, the potential to make a significant contribution to climate change mitigation and meeting the United Nation’s sustainable development goals through the rational improvement of new and established fungal cell factories. The White Paper presented here is the result of the 2nd Think Tank meeting held by the EUROFUNG consortium in Berlin in October 2019. This paper highlights discussions on current opportunities and research challenges in fungal biotechnology and aims to inform scientists, educators, the general public, industrial stakeholders and policymakers about the current fungal biotech revolution.

Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) disease, infects cucurbit crops including watermelon and melon. This bacterium can enter the viable but nonculturable (VBNC) state following exposure to copper sulfate. Moreover, copper-induced VBNC A. citrulli cells can be resuscitated by EDTA. In this study, isobaric tag for relative and absolute quantification (iTRAQ) was used to compare protein profiles of VBNC cells, resuscitated cells at different stages and log-phase cells of the A. citrulli model strain AAC00-1. A total of 2672 proteins were identified, with 60 being differentially abundant in VBNC cells compared with log-phase cells, and 469 being differentially abundant in resuscitated cells compared with VBNC cells. Proteins involved in the arginine and proline metabolism pathway and degradation of aromatic compounds could be important for the VBNC cells. In the early resuscitation process, proteins associated with carbon metabolism, and degradation of naphthalene and aromatic compounds were significantly enriched, while proteins involved in oxidative phosphorylation, bacterial chemotaxis, ABC transporters and quorum sensing were significantly enriched at the late resuscitation stages. This is the first study reporting thorough protein profile analyses of VBNC and resuscitating cells of a plant-pathogenic bacterium. Biological significance: The VBNC state is a dormant-like condition that was reported to occur in many bacterial species, upon facing a variety of environmental stresses. Acidovorax citrulli is a seed borne pathogenic bacterium that threatens cucurbit production worldwide. Moreover, A. citrulli can enter into the VBNC state after treatment of copper sulfate, thus increasing its survival and dissemination probabilities. This study enriches our understanding of the mechanisms of entrance into and resuscitation from the VBNC state of this important plant-pathogenic bacterium. This knowledge could be exploited in the future to develop novel approaches to interfere with these processes, thus contributing to a more efficient management of this pathogen. In a broader perspective, the knowledge emerging from this study has implications to the general understanding of the VBNC state in bacteria. © 2019 Elsevier B.V.