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Cistaceae are shrubs, subshrubs and herbs that often occur in stressful, fire-prone or disturbed environments and form ectomycorrhizal (ECM) associations with symbiotic fungi. Although some Cistaceae are long-lived shrubs that grow to significant size, others are herbaceous annuals or short-lived plants. Thus, Cistaceae are atypical ECM hosts that are fundamentally different in their biology from trees that are the more typically studied ECM hosts. The Mediterranean region is the center of diversity for Cistaceae and the ectomycorrhizal fungi associated with Cistaceae hosts have primarily been studied in Europe, North Africa, and the Middle East. Mediterranean Cistaceae often host diverse communities of ECM fungi, but they also act as hosts for some ECM fungi that putatively show host-specificity or strong host preference for Cistaceae (including species of Delastria, Hebeloma, Terfezia, and Tirmania). The ECM associations of Cistaceae in North America, however, remain highly understudied. Here we use fungal DNA metabarcoding to document the ectomycorrhizal fungal communities associated with Crocanthemum and Lechea (Cistaceae) in open, fire-prone sandhill habitats in north Florida. At each site we also sampled nearby Pinus to determine whether small, herbaceous Cistaceae have specialized ECM fungi or whether they share their ECM fungal community with nearby pines. The ECM communities of Florida Cistaceae are dominated by Cenococcum (Ascomycota) and Russula (Basidiomycota) species but were also significantly associated with Delastria, an understudied genus of mostly truffle-like Pezizales (Ascomycota). Although many Cistaceae ECM fungi were shared with neighboring pines, the ECM communities with Cistaceae were nonetheless significantly different than those of pines. 

Truffle fungi are esteemed for their aromatic qualities and are among the most widely cultivated edible ectomycorrhizal fungi. Here we document a successful method for establishing Tuber lyonii , the pecan truffle, on pecan ( Carya illinoinensis ) seedlings in a field setting. We assessed the impacts of soil fumigation and varying concentrations of truffle spore inoculum on the ectomycorrhizal fungal and the complete fungal communities as well as the colonization of T. lyonii on pecan roots at three nurseries in Georgia, United States. To identify fungal communities on pecan seedlings, we performed high-throughput amplicon sequencing of the fungal ITS1 rDNA region. Our 5-year long field experiment demonstrates that fumigation and inoculation together resulted in the highest persistence of T. lyonii on pecan roots. While fungal OTU numbers fluctuated over the years of our experiments, there was no statistical support to demonstrate diversification of communities when Shannon diversity metrics were used. However, we did find that older seedlings were less likely to be dominated by T. lyonii compared to younger ones, suggesting successional changes in the fungal community over time. This suggests that transplanting inoculated seedlings after 2 or 3 years post-inoculation is optimal for future truffle propagation efforts. Our results demonstrate that T. lyonii can be established in situ with methods that are compatible with current pecan nursery industry practices and that fungal communities on pecan seedlings vary depending on the experimental treatments used during planting. While the pecan truffle is not yet widely cultivated, our results provide insights for future large-scale cultivation of this and perhaps other Tuber species. 

One of the main threats to forests in the Anthropocene are novel or altered interactions among trees, insects and fungi. To critically assess the contemporary research on bark beetles, their associated fungi, and their relationships with trees, the international Bark Beetle Mycobiome research coordination network has been formed. The network comprises 22 researchers from 17 institutions. This forward-looking review summarizes the group’s assessment of the current status of the bark beetle mycobiome research field and priorities for its advancement. Priorities include data mobility and standards, the adoption of new technologies for the study of these symbioses, reconciliation of conflicting paradigms, and practices for robust inference of symbiosis and tree epidemiology. The Net work proposes contemporary communication strategies to interact with the global community of researchers studying symbioses and natural resource managers. We conclude with a call to the broader scientific community to participate in the network and contribute their perspectives.