Rescuing the ectomycorrhizal biodiversity associated with South American Nothofagaceae forest, from the 19th century naturalists up to molecular biogeography

Abstract

The southernmost portion of the Andes in South America hosts Nothofagaceae forests that form ectomycorrhizal (EcM) associations. We compiled all the published reports of EcM taxa from these woodlands, based on fruit-body collections and molecularly identified root tips. This resulted in 87 peer-reviewed research papers dealing with EcM associations from Nothofagaceae forests published over the past 62 years. Based on these papers the EcM richness and its association with Nothofagaceae species was analyzed. Represented by 45 genera (34 Basidiomycetes and 11 Ascomycetes), 479 EcM taxa have been recorded, plus an additional 46 EcM taxa which are potentially EcM. Cortinarius was the most frequent and diverse genus, with 64.9% of total species. Nothofagus dombeyi had the highest number of unique EcM species, followed by N. pumilio, N. antarctica and Lophozonia obliqua. The EcM community associated with Nothofagus species, except N. nitida, showed higher similarities among themselves, than with Lophozonia and Fuscospora species. Beta diversity indexes showed EcM Nothofagus species have 29–42% niche overlap, while Nothofagus—Lophozonia only had 1–16%. The assessment of the accuracy of the EcM diversity, host specificity and community structure deserve further studies combining phylogenetic analysis based on broad ecological surveys. On the basis of pre-selected criteria Austropaxillus statuum, Cortinarius fragilis, Cortinarius xiphidipus and Hallingea purpurea are proposed as candidates for nursery spore inoculations, and should be subject to scientific evaluation to determine costs and benefits.

Loose Ends in the Cortinarius Phylogeny: Five New Myxotelamonoid Species Indicate a High Diversity of These Ectomycorrhizal Fungi with South American Nothofagaceae

“…Several Cortinarius species described from Patagonia are thought to associate only with a specific Nothofagaceae host tree species, including, C. magellanicus Speg., C. horakii Valenz. & Esteve-Rav., C. magellanicoalbus Salgado Salomón & Peintner, C. austronanceiensis (Moser) Garnier, C. capitellinus Horak, C. cinereus Moser, C. brachyspermus Peintner & Moser, C. glutinopallens (Horak) Peintner & Moser, C. cretaceus (Horak) Horak and C. roblerauli Salgado Salomón & Peintner [ 1 ]. Due to undersampling and the difficult taxonomy of Cortinarius in Patagonia, it is possible that specific host associations could be more frequent than previously assumed.…”

“…Within the genus Cortinarius there are also several ectomycorrhizal species with more generalist plant host associations, such as C. albocanus (Horak & Moser) Peintner & Moser, C amoenus (Moser & Horak) Garnier, C. austroduracinus Moser, C. austrosalor Moser, C. collariatus Horak & Moser and C. flammuloides Horak & Moser. They are all reportedly associated with Nothofagaceae species present in Patagonia [ 1 ]. We observed the same generalist pattern for C. voluptatis and C. neuquensis , which are associated with both Lophozonia and Nothofagus spp.…”

“…However, fungi occurring in the Southern Hemisphere are still largely under-represented in public databases [ 61 ], and data concerning their diversity and distribution are far from being complete, even when Cortinarius spp. are often quite dominant in studies of ectomycorrhizal fungi communities on roots and in soil [ 1 , 13 , 61 , 68 , 69 ]. This is especially true and important for fungal groups with immense species richness like Cortinarius , a widespread and important ectomycorrhizal genus from the South American Nothofagaceae forests with high ecological, forest restoration interests, and important non-timber forest products.…”

“…Cortinarius (Pers.) Gray is the most species-rich ectomycorrhizal genus in South American Nothofagaceae forests [ 1 ]. Due to their ectomycorrhizal role, Cortinarius species are critical for nutrient cycling in forests, especially at higher latitudes [ 2 ].…”

Uso de la secuenciación de segunda generación (NGS) para descubrir la diversidad de hongos degradadores de la madera en los bosques Andino Patagónicos

“…Ambas especies de Nothofagus presentan una situación distintiva de muerte en pie progresiva que exhibe un patrón espacial agrupado y del cual se han recuperado patógenos fúngicos potenciales, pero sin conducir a ninguna etiología patógena fúngica primaria (de Errasti et al, 2015;Molina et al, 2020;Pildain et al, 2009). Hay antecedentes, acumulados durante las últimas décadas de investigación, sobre la diversidad de hongos asociados a estos árboles en ciertos grupos, como políporos, ectomicorrizas, hongos ofiostomatoides y otros hongos de descomposición (Barroetaveña et al, 2019;de Errasti et al, 2016;Rajchenberg, 2006). Se sabe que esta micobiota juega un papel clave en la aptitud y el funcionamiento de los árboles a través de dinámicas complejas (Baldrian, 2016) y expresadas a lo largo de un continuo de mutualismo, comensalismo y parasitismo que puede transcurrir, incluso, durante la vida del mismo organismo fúngico (Robinson et al, 2004).…”