Jacob Golan

Societal Impact Statement: As herbaria digitize millions of plant specimens, ethnobotanical information associated with them is becoming increasingly accessible. These biocultural data include plant uses, names, and/or management practices of Indigenous Peoples and Local Communities (IPLCs). However, the absence of shared curatorial standards limits accessibility and use by IPLCs and others. We estimated and characterized ethnobotanical data associated with herbarium specimens and provide here key considerations for future work. We identified a proportionally small, yet collectively significant, number of ethnobotanical specimens, and call for coordinating best practices among global herbaria to locate, acknowledge, and responsibly share this information, together with source communities. Summary: As herbaria digitize millions of plant specimens, those containing biocultural information are becoming increasingly accessible. This information — also known as ethnobotanical data — holds both cultural and scientific value, and may include plant uses, vernacular names, local species concepts, cultural values, and plant management practices of Indigenous Peoples and Local Communities (IPLCs). However, the lack of coordinated curatorial standards currently limits both the accessibility and effective use of this information by IPLCs, ethnobotanists, and others. To address this gap, we quantitatively estimated and characterized ethnobotanical information associated with herbarium specimens and offer key considerations to guide future work. We identified a proportionally small —yet collectively significant— number of ethnobotanical specimens, comprising approximately 1.6% of all specimen records and representing hundreds of thousands of specimens in the surveyed herbaria. We advocate for coordinating best practices to locate, acknowledge, and ethically share this information among herbaria, working together with source communities and through global cooperation.

Summary: Global change is reshaping Earth's biodiversity, but the changing distributions of nonpathogenic fungi remain largely undocumented, as do mechanisms enabling invasions. The ectomycorrhizal Amanita phalloides is native to Europe and invasive in North America. Using population genetics and genomics, we sought to describe the life history traits of this successfully invading symbiotic fungus. To test whether death caps spread underground using hyphae, or aboveground using sexual spores, we mapped and genotyped mushrooms from European and US sites. Larger genetic individuals (genets) would suggest spread mediated by vegetative growth, while many small genets would suggest dispersal mediated by spores. To test whether genets are ephemeral or persistent, we also sampled from populations over time. At nearly every site and across all time points, mushrooms resolve into small genets. Individuals frequently establish from sexual spores. But at one Californian site, a single individual measuring nearly 10 m across dominated. At two Californian sites, the same genetic individuals were discovered in 2004, 2014, and 2015, suggesting single individuals (both large and small) can reproduce repeatedly over relatively long timescales. A flexible life history strategy combining both mycelial growth and spore dispersal appears to underpin the invasion of this deadly perennial ectomycorrhizal fungus.

A frequently ignored but critical aspect of microbial dispersal is survival in the atmosphere. We exposed spores of two closely related, morphologically dissimilar, and economically important fungal pathogens to typical atmospheric environments and modeled their movement in the troposphere. We first measured the mortality of Alternaria solani and A. alternata conidia exposed to ranges of solar radiation, relative humidity, and temperature. We then measured survival in an advantageous environment over 12 days. A. solani conidia are nearly 10 times larger than A. alternata conidia and most die after 24 hours. By contrast, over half of A. alternata conidia remained viable at 12 days. The greater viability of the smaller spores is counterintuitive as larger spores are assumed to be more durable. To elucidate the consequences of survival rates for dispersal, we deployed models of atmospheric spore movement across North American. We predict 99% of the larger A. solani conidia settle within 24 hours, with a maximum dispersal distance of 100 km. By contrast, most A. alternata conidia remain airborne for more than 12 days and long-distance dispersal is possible, e.g., from Wisconsin to the Atlantic Ocean. We observe that the larger conidia of A. solani survive poorly but also land sooner and move over shorter distances as compared to the smaller conidia of A. alternata . Our data relating larger spore size to poorer survival in the atmosphere and shorter distances travelled likely translate to other fungal species and highlight the potential for starkly different dispersal dynamics among even closely related fungi.

Populations of the entomopathogenic fungus Batkoa major were analyzed using sequences of four genomic regions and evaluated in relation to their genetic diversity, insect hosts and collection site. This entomophthoralean pathogen killed numerous insect species from 23 families and five orders in two remote locations during 2019. The host list of this biotrophic pathogen contains flies, true bugs, butterflies and moths, beetles, and barkflies. Among the infected bugs (Order Hemiptera), the spotted lanternfly (Lycorma delicatula) is a new invasive planthopper pest of various woody plants that was introduced to the USA from Eastern Asia. A high degree of clonality occurred in the studied populations and high gene flow was revealed using four molecular loci for the analysis of population structure. We did not detect any segregation in the population regarding host affiliation (by family or order), or collection site. This is the first description of population structure of a biotrophic fungus-generalist in the entomopathogenic Order Entomophthorales. This analysis aimed to better understand the potential populations of entomopathogen-generalists infecting emerging invasive hosts in new ecosystems.

The ectomycorrhizal death cap Amanita phalloides is native to Europe but invasive in North America. To understand whether the fungus spreads underground using hyphae, or above ground using sexual spores, we mapped and genotyped sporocarps from European and American populations. Larger genetic individuals (genets) would suggest spread mediated by vegetative growth, while many small genets would suggest dispersal mediated by spores. To test whether genets are ephemeral or persistent, we also sampled from the same invasive populations over time. We mapped 13 European and American populations between 2004-2007 and characterized each using amplified fragment length polymorphisms (AFLP). In 2014 and 2015, we resampled populations in California and added three new European populations. These populations and a subset of the specimens originally collected in 2004 were characterized using whole genome sequencing. In every population and across all time points, sporocarps resolve into small, apparently short-lived genets. Sporocarps nearer each other are more closely related, suggesting spores land and germinate near parent sporocarps. A. phalloides uses spores to move across landscapes. Spores travel very short distances and individuals appear ephemeral. The death cap’s life history suggests yearly sporocarp removal as a strategy for control of this deadly fungus.