Increasing nickel (Ni) demand may spur the need for creative Ni production methods. Agromining (farming for metals) uses plants that can accumulate high concentrations of metal in their biomass, called bio-ore, as a metal extraction strategy. Furthermore, biochar, produced by biomass pyrolysis under low-oxygen conditions, can be used to remove Ni from contaminated wastewaters. In this work we investigate whether biochar synthesized from the Ni-hyperaccumulating plant Odontarrhena chalcidica (synonymous Alyssum murale ) can be used as a Ni-adsorbing biochar. We grew O. chalcidica on soils with varying Ni concentration, characterized the plants and resultant biochars synthesized at different pyrolysis temperatures, and analyzed Ni batch adsorption results to determine the adsorption capacity of O. chalcidica biochar. We found that Ni concentration in O. chalcidica increases with increasing soil Ni but reaches an accumulation limit around 23 g Ni kg –1 dry weight in dried leaf samples. Pyrolysis concentrated Ni in the biochar; higher pyrolysis temperatures led to higher biochar Ni concentrations (max. 87 g Ni kg –1 ) and surface areas (max. 103 m 2 /g). Finally, the O. chalcidica biochar adsorption results were comparable to high-performing Ni adsorbents in the literature. The adsorption process greatly increased the Ni concentration in some biochars, indicating that synthesizing biochar from O. chalcidica biomass and using it as a Ni adsorbent can produce a Ni-enhanced bio-ore with nickel content higher than all nickel-rich veins currently mined.

Opportunistic yeast pathogens arose multiple times in the Saccharomycetes class, including the recently emerged, multidrug-resistant Candida auris. We show that homologs of a known yeast adhesin family in Candida albicans, the Hyr/Iff-like (Hil) family, are enriched in distinct clades of Candida species as a result of multiple, independent expansions. Following gene duplication, the tandem repeat-rich region in these proteins diverged extremely rapidly and generated large variations in length and β-aggregation potential, both of which were known to directly affect adhesion. The conserved N-terminal effector domain was predicted to adopt a β-helical fold followed by an α-crystallin domain, making it structurally similar to a group of unrelated bacterial adhesins. Evolutionary analyses of the effector domain in C. auris revealed relaxed selective constraint combined with signatures of positive selection, suggesting functional diversification after gene duplication. Lastly, we found the Hil family genes to be enriched at chromosomal ends, which likely contributed to their expansion via ectopic recombination and break-induced replication. Combined, these results suggest that the expansion and diversification of adhesin families generate variation in adhesion and virulence within and between species and are a key step toward the emergence of fungal pathogens.

Opportunistic yeast pathogens evolved multiple times in the Saccharomycetes class. A recent example is Candida auris, a multidrug resistant pathogen associated with a high mortality rate and multiple hospital outbreaks. Genomic changes shared between independently evolved pathogens could reveal key factors that enable them to infect the host. One such change may be the expansion of cell wall adhesins, which mediate biofilm formation and adherence and are established virulence factors in Candida spp. Here we show that homologs of a known adhesin family in C. albicans, the Hyr/Iff-like (Hil) family, repeatedly expanded in divergent pathogenic Candida lineages including in C. auris. Evolutionary analyses reveal varying levels of selective constraint and a potential role of positive selection acting on the ligand-binding domain during the family expansion in C. auris. The repeat-rich central domain evolved rapidly after gene duplication, leading to large variation in protein length and β-aggregation potential, both known to directly affect adhesive functions. Within C. auris, isolates from the less virulent Clade II lost five of the eight Hil homologs, while other clades show abundant tandem repeat copy number variation. We hypothesize that expansion and diversification of adhesin gene families are a key step towards the evolution of fungal pathogens and that variation in the adhesin repertoire could contribute to within and between species differences in the adhesive and virulence properties.

The multiscale, complex challenges at the nexus of food, energy, and water systems (FEWS) demand approaches to graduate education beyond traditional disciplinary training. Here, we present a vision for training FEWS leaders developed by faculty and students from interdisciplinary graduate training programs focused on the FEWS nexus. We discuss the imperative to create interdisciplinary, next-generation FEWS leaders and the core skills and proficiencies such leaders need: employ systems thinking, thrive in interdisciplinary teams, communicate effectively, and engage diverse stakeholders and communities. These skills will prepare students to connect science to innovative, actionable solutions and to successfully lead across a variety of careers. Graduate training that integrates these approaches must, on the one hand, overcome structural, cultural, and financial barriers in higher education, but on the other hand, will help develop a community of practice capable of developing sustainable solutions for the FEWS nexus and other vexing environmental challenges.