Lack of knowledge on ecological determinants and cryptic lifestyles hinder our understanding of Terfezia diversity.

Developing below the soil surface desert, truffles are hard to find. Within Terfezia genus, at least 18 species are described and many are endemic to the Mediterranean basin. Ecological and geographic information are key factors for species diagnosis, and so far Terfezia species are believed to be linked to either acidic or basic soils or to specific plant hosts. Thus, we have looked at Terfezia diversity within a relatively homogeneous geographical area in Portugal that is suitable for these species and that covered different soils and different dominant host species. We analyzed the observed intraspecific variability within the context of species ecological preferences (e. g. edaphic and putative host). One of our major findings was the discovery of T.grisea in acid soils in association with Tuberariaguttata, a puzzling information since, until now, this species was only found in alkaline soils. We also report on the linkage of different Terfezia lineages within species and ecologic parameters such as soil texture, soil pH and plant host. Additionally, by placing the collected specimens on the most recent genus phylogeny based on the ITS region, we also updated the number of known Terfezia species occurring in Portugal from three to ten. Terfeziadunensis is here reported for the first time for Portugal. Overall, our results show that the exploration of undersampled sites reveals itself as a good strategy to disclose unknown aspects of desert truffle diversity and ecology. These aspects are of prime importance when considering the economic value of the desert truffles for rural populations in the Mediterranean basin.

Morphological Characterization of the In Vitro Mycorrhizae Formed between Four Terfezia Species (Pezizaceae) with Cistus salviifolius and Cistus ladanifer-Towards Desert Truffles Production in Acid Soils.

Terfezia species are obligate symbiotic partners of several xerophytic host plants, mainly belonging to the Cistaceae. Yet, their mycorrhizal associations with members of the genus Cistus remain poorly characterized and their potential application in desert truffle cultivation remains unexplored. This work provides the first anatomic descriptions of the mycorrhizae formed in vitro by four Terfezia species (i.e., T. arenaria; T. extremadurensis; T. fanfani, T. pini) with C. ladanifer and C. salviifolius, two of the most widespread and common Cistus species in acidic soils. All the tested associations resulted in the formation of ectomycorrhizae with well-developed Hartig net, but with a varying degree of mantle development. Our results also demonstrate that all the experimented Terfezia-Cistus combinations expressed high mycorrhization rates. Moreover, the present work shows that C. salviifolius and C. ladanifer are suitable plant hosts for Terfezia species, including some that are, to date, known to be only associated with annual herbs or tree species. This new evidence might aid in broadening the number of situations whereby Terfezia spp. can be cultivated in acid soils.

Macrofungi of Mata da Margaraça (Portugal), a relic from the Tertiary Age.

Mata Nacional da Margaraça represents a rare example where the Atlantic climate influences the perpetuity of a small enclave of a previously widespread laurel forest. The higher relative humidity values (> 80%), which are almost constant all year long and the mild temperatures, rarely exceeding 30°C, even in the dry season (June to September), create an insular-like effect. The biological communities of Margaraça exhibit a transitory character. The forest is dominated by Quercus robur and Castanea sativa, yet Quercus suber, although less frequent, can also be found. The laurel species, such as Viburnum tinus, Ilex aquifolium, Laurus nobilis and the Portuguese endemic Prunus lusitanica ssp. lusitanica, relics from the ancient Portuguese Tertiary, comprise the understorey. The present work represents, to the best of our knowledge, the first regional macrofungal species list of the Mata da Margaraça published to date. The recent fires that occurred in the area have provided the opportunity to study the post-fire communities. The surveys were carried out in 2004 and later in 2018-2019. A total of 271 species were registered as belonging to Basidiomycota (≈ 80%) and Ascomycota (≈ 20%). The most represented Basidiomycota families were Russulaceae, Mycenaceae and Agaricaceae and the most represented Ascomycota families were Pyronemataceae and Pezizaceae. The new records to Portugal add up to a total of 88 species and another 116 species are new records to the province of Beira Litoral. Post-fire fungi account for 17 of the total of 271 species registered in these studies and most of these species are new to Portugal.

What is in a name? Terfezia classification revisited.

Desert truffles (mycorrhizal hypogeous Ascomycota) are found in arid and semi-arid areas of the globe and have great ecological and economic importance. Terfezia is undoubtedly the most diversified of all desert truffle genera, but its taxonomy is far from resolved. Specifically, the large number of newly described species plus the high intraspecific morphological variability observed within some Terfezia lineages as rendered the use of molecular techniques mandatory for specimen's discrimination. But the subsequent increasing amount of sequence data produced also a huge number of undescribed taxa that required determination. We compiled and used the public available ITS data on Terfezia spp. on the custom-curated UNITE database to reconstruct the genus phylogeny. We found at least 17 distinct lineages within the genus and successfully resolved some of the more pressing taxonomic issues, namely the T. leptoderma/olbiensis complex and some misapplied synonymy. Based on this resolved phylogeny, and motivated by the recent new described species, we proposed an identification key to Terfezia genus highlighting the importance of morphological and ecological characterization.