In vitro anti-tumoral and immunomodulatory effects of acidic polysaccharides isolated from the fungus Gloeosoma mirabile.

Polysaccharides from wood-rooting fungi have attracted attention due to their broad pharmacological properties. Herein, we report the antitumor and immunomodulatory activities of acid polysaccharides isolated from fungi Gloeosoma mirabile. The polysaccharide extracts displayed significant antiproliferative activity against cancer cell lines (MCF-7, HCT-116, U-937) in a dose-dependent manner and induction of IL-6 in macrophage RAW 264.7. Furthermore, flow cytometry analysis showed that high polysaccharide concentrations induced apoptosis by 83% in HL-60 cells. Based on gas chromatography-mass spectrometry (GC-MS) and Fourier transform infra-red (FT-IR) spectroscopy studies, acidic polysaccharides from G. mirabile were mainly composed of arabinose, α-D-galactopyranose and methyl ß-D-galactopyranoside.

Effect of Huntiella decorticans and drought on Nothofagus dombeyi seedlings.

In the temperate forests of Patagonia, Argentina, Nothofagus dombeyi, commonly known as Coihue, has shown sensitivity to intense drought events, leading to mortality. Studies have been conducted on Coihue decline and mortality using a variety of approaches, including the role of extreme heat waves and drought, pests and pathogens, particularly the fungus Huntiella decorticans. This work aimed to evaluate survival, vitality, necrosis extension and growth response of inoculated and non-inoculated Coihue seedlings from different provenances exposed to different soil moisture levels. To achieve this goal, 96 Coihue seedlings from 2 different provenances were assigned to 8 different experimental treatments. Treatments were composed of the presence or absence of H. decorticans and different soil moisture content conditions, dry, wet and the exposure to dry condition at different times of the experiment. Both dry conditions and H. decorticans had negative effects on the survival and growth rate of Coihue. The combination of both factors resulted in 100 % mortality, regardless of the plants' geographical provenances. Mortality began to be observed 3 months after pathogen inoculation, during the warmest month. Necrosis extension produced by the pathogen was similar for most of the inoculated treatments. The treatment under wet condition during the experiment but subjected to dry condition in the previous growing season presented lower necrosis extension (8.4 ±â€…3.2 %), than the other treatments. The radial increase was also affected by the treatments and geographical provenance, being those plants exposed to dry conditions which grew less (0.19 ±â€…0.21 mm). This study enhances our understanding of the plant-pathogen interaction. According to our results, Coihue may become more susceptible to mortality, when H. decorticans and water deficit conditions act synergistically.

The Global Forest Health Crisis: A Public-Good Social Dilemma in Need of International Collective Action.

Society is confronted by interconnected threats to ecological sustainability. Among these is the devastation of forests by destructive non-native pathogens and insects introduced through global trade, leading to the loss of critical ecosystem services and a global forest health crisis. We argue that the forest health crisis is a public-good social dilemma and propose a response framework that incorporates principles of collective action. This framework enables scientists to better engage policymakers and empowers the public to advocate for proactive biosecurity and forest health management. Collective action in forest health features broadly inclusive stakeholder engagement to build trust and set goals; accountability for destructive pest introductions; pooled support for weakest-link partners; and inclusion of intrinsic and nonmarket values of forest ecosystems in risk assessment. We provide short-term and longer-term measures that incorporate the above principles to shift the societal and ecological forest health paradigm to a more resilient state.

Sapwood mycobiome varies across host, plant compartment and environments in Nothofagus forests from Northern Patagonia.

Global forests are increasingly being threatened by altered climatic conditions and increased attacks by pests and pathogens. The complex ecological interactions among pathogens, microbial communities, tree hosts and the environment are important drivers of forest dynamics. Little is known about the ecology of forest pathology and related microbial communities in temperate forests of the southern hemisphere. In this study, we used next-generation sequencing to characterize sapwood-inhabiting fungal communities in North Patagonian Nothofagus forests and assessed patterns of diversity of taxa and ecological guilds across climatic, site and host variables (health condition and compartment) as a contribution to Nothofagus autecology. The diversity patterns inferred through the metabarcoding analysis were similar to those obtained through culture-dependent approaches. However, we detected additional heterogeneity and greater richness with culture-free methods. Host species was the strongest driver of fungal community structure and composition, while host health status was the weakest. The relative impacts of site, season, plant compartment and health status were different for each tree species; these differences can be interpreted as a matter of water availability. For Nothofagus dombeyi, which is distributed across a wide range of climatic conditions, site was the strongest driver of community composition. The microbiome of N. pumilio varied more with season and temperature, a relevant factor for forest conservation in the present climate change scenario. Both species carry a number of potential fungal pathogens in their sapwood, whether they exhibit symptoms or not. Our results provide insight into the diversity of fungi associated with the complex pathobiome of the dominant Nothofagus species in southern South America.

Los bosques del mundo están cada vez más amenazados por las condiciones climáticas alteradas y el aumento de los ataques de plagas y patógenos. Las complejas interacciones ecológicas entre los patógenos, las comunidades microbianas, los árboles hospedantes y el medio ambiente son impulsores importantes de la dinámica forestal. Poco se sabe sobre la ecología de la patología forestal y las comunidades microbianas relacionadas en los bosques templados del hemisferio sur. En este estudio, utilizamos la secuenciación Illumina para caracterizar las comunidades de hongos que habitan en la albura en los bosques de Nothofagus de la Patagonia Norte y evaluamos los patrones de diversidad de taxones y gremios ecológicos a través de variables climáticas, de sitio y de hospedante (identidad, condición de salud y compartimento) como una contribución a la autoecología de los Nothofagus. Los patrones de diversidad inferidos a través del análisis metabarcoding fueron similares a los obtenidos a través de enfoques dependientes de cultivo. Sin embargo, detectamos mayor heterogeneidad y mayor riqueza con métodos independientes de cultivo. La especie hospedante fue el modelador más fuerte de la estructura y composición de la comunidad fúngica, mientras que el estado de salud del hospedante fue el más débil. El impacto relativo del sitio, la estación, el compartimento y el estado de salud fueron diferentes para cada especie de árbol; estas diferencias pueden interpretarse en clave de disponibilidad de agua. Para N. dombeyi, que se distribuye a lo largo de una amplia gama de condiciones climáticas, el sitio fue el principal modelador de la composición de la comunidad. El micobioma de Nothofagus pumilio varió más con la estación y la temperatura, un factor relevante para la conservación de los bosques en el escenario actual de cambio climático. Ambas especies portan una serie de patógenos fúngicos potenciales en su albura, ya sea que muestren síntomas o no. Nuestros resultados brindan una idea de la diversidad de hongos asociados con el complejo patobioma de las especies dominantes de Nothofagus en el sur de América del Sur.

Species and genera in Aleurodiscus sensu lato as viewed from the Southern Hemisphere.

Phylogenetic relationships of 12 species in Aleurodiscus sensu lato (Stereaceae, Russulales) described from the Patagonian forests of Chile and Argentina were investigated based on sequences of nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and the D1-D2 domains of nuc 28S rDNA (28S). A new genus and a new species are presented, and 10 new combinations proposed. The genus Gloeosoma is shown to be phylogenetically well supported and morphologically circumscribed; it includes G. vitellinum (type species), G. mirabile, comb. nov., G. zealandicum, comb. nov., and Gloeosoma decorticans, sp. nov., which is newly described from Chile. The new genus Stereodiscus is proposed to accommodate a group of taxa characterized by an austral distribution and morphologically by smooth, thin-walled, amyloid basidiospores and a lack of gloeocystidia and acanthocystidia; three species develop Stereum-like basidiomata and two species present discoid ones. The new genus includes the species formerly known as Aleurodiscus antarcticus, A. limonisporus, A. parmuliformis, A. patagonicus, and A. triviale. Specimens of Stereodiscus parmuliformis (A. parmuliformis) from New Zealand (where it was originally described) and southern Chile are shown to be phylogenetically conspecific, which confirms its presence in Patagonia. Gloeosoma and Stereodiscus are shown to be distantly related to Aleurodiscus s. str. and other genera in Stereaceae. The new combinations Aleurocystidiellum bernicchiae, Aleurocystidiellum hallenbergii, and Acanthobasidium quilae are proposed based on morphology and phylogenetic analyses, and Aleurodiscus cerussatus is shown to be a cryptic species complex.

Understanding introduction history: Genetic structure and diversity of the edible ectomycorrhizal fungus, Suillus luteus, in Patagonia (Argentina).

Suillus luteus is a common ectomycorrhizal (EM) fungus associated with several Pinus species. It is distributed throughout the Northern Hemisphere and has been introduced into South America and New Zealand. We examined the genetic structure and population biology of S.luteus, which was introduced into Patagonian plantations with Pinus species in Argentina. Overall, 106 samples were collected at 11 geographically separated sites (i.e., Pinus plantations) along a latitudinal gradient in Patagonia (ca. 38°-46° south latitude). Phylogenetic analyses confirmed placement in S.luteus. Genetic analysis demonstrated moderate within-site genetic diversity, but low differentiation between sites. No clear clusters were detected geographically or in relation to host species of Pinus. Our results suggest that the weak genetic structure of the species reflects the short time that has elapsed since the introduction of S.luteus into Patagonia, and its expansion with exotic afforestation there. Moreover, the lack of structure is consistent with a founder effect, suggesting the introduction of a small number of genets that spread throughout all the plantations. Therefore, the high level of gene flow and weak genetic structure observed are probably related to the anthropogenic movement of inoculum associated with forestry practices.

Diversity of exotic ectomycorrhizal Rhizopogon from pine plantations in Patagonia.

We present an account of Rhizopogon introduced from plantings of exotic pine plantations in Argentine Patagonia. Nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) and nuc 28S rDNA (28S) sequences were used to identify specimens from Argentina and examine their relationships with geographically different Rhizopogon species. Based on phylogenetic analyses, we confirm that four species of Rhizopogon occur in pine plantations across Patagonia. Several Rhizopogon collections from Pinus ponderosa plantations across different provinces cluster with R. arctostaphyli, a species within R. subg. Amylopogon. The majority of Patagonian Rhizopogon, however, form three different lineages in R. subg. Roseoli. The first of these, R. roseolus sensu Trappe, includes numerous collections from Pinus ponderosa, P. contorta, and P. radiata stands of North American affiliation. The second, R. roseolus sensu Martin and Garcia from P. ponderosa plantations, clusters in clade IIIa of the R. roseolus complex, which also includes the holotype collection of R. mohelnensis from the Czech Republic. The third species in R. subg. Roseoli, and fourth species overall from Patagonia, is R. granuloflavus from Pinus ponderosa plantations. Multiplex polymerase chain reaction (PCR) of numerous Roseoli samples failed to produce an amplicon indicative of either Japanese or New Zealand shoro.

A discussion on the genus Fomitiporella (Hymenochaetaceae, Hymenochaetales) and first record of F.americana from southern South America.

Fomitiporella has traditionally been delimited based on the gross morphology of the basidiomes, hyphal structure and basdiospores. Recently, phylogenetic studies supported the incorporation of an extensive number of species within the genus. Although most of its species are nested in the 'Phellinotus clade' (Hymenochaetaceae, Basidiomycota), genera such as Arambarria, Inocutis and Phellinotus were not included in previous analysis. To further our understanding of the genus, new sequences from 28S and ITS nuc rDNA genes were jointly analysed with a large selection of taxa in the 'Phellinotus clade', also with re-examination of morphological and ecological data. Results showed several lineages in what has hitherto been considered to represent Fomitiporella, indicating that the genus is paraphyletic as presently circumscribed. There is a well-supported Fomitiporella core group that includes the type species and nine other monophyletic lineages with high support, of which those representing Arambarria, Inocutis and Phellinotus are distinct from the Fomitiporella core group by macro and micromorphological traits and/or biogeographic distribution. Fomitiporellaamericana, a species described from SE USA, was found in the Patagonian forests of southern Argentina and Chile; it is the taxon responsible for the white heart-rot found on standing Austrocedruschilensis and one of the taxa decaying wooden tiles of historic churches in Chiloé Is., Chile.

The phylogenetic position of poroid Hymenochaetaceae (Hymenochaetales, Basidiomycota) from Patagonia, Argentina.

Six poroid Hymenochaetaceae from Patagonia, Argentina, were studied phylogenetically with nuc rDNA internal transcribed spacer (ITS) and partial 28S rDNA sequences, together with morphological data. Two new genera and a new species are introduced as well as two new combinations proposed. Arambarria destruens gen. et sp. nov. is proposed for a taxon fruiting on fallen or standing, dead Diostea juncea and Lomatia hirsuta and previously recorded erroneously as Inocutis jamaicensis; it is distinguished by annual, effused to effused-reflexed basidiomes forming pilei, a monomitic hyphal system, thick-walled and yellowish basidiospores (brownish chestnut in potassium hydroxide solution), lack of a granular core in the context and lack of setoid elements. Nothophellinus gen. nov. is proposed to accommodate Phellinus andinopatagonicus, the main white wood-rotting polypore of standing Nothofagus pumilio and also an important wood-decayer of other Nothofagus species from southern Argentina and Chile. It is morphologically similar to Phellopilus (type species P. nigrolimitatus) but differs by lacking setae. The new combinations Pseudoinonotus crustosus and Phellinopsis andina are proposed for Inonotus crustosus and Phellinus andinus, respectively. Phellinus livescens, which decays the sapwood of several standing Nothofagus species, is closely related to Phellinus uncisetus, a Neotropical species related to Fomitiporia; for the time being P. livescens is retained in Phellinus sensu lato. An unidentified taxon responsible for a white heart-rot in living Austrocedrus chilensis grouped with Phellinus caryophyllii and Fulvifomes inermis, but its generic affinities remain ambiguous. Transmission electron microscopy studies confirm this unidentified taxon has an imperforate parenthesome, which is typical of the Hymenochaetaceae.

Phylogenetic relationships of Hydnum peroxydatum support the synonymy of Hydnochaete with Hymenochaete (Hymenochaetaceae, Agaricomycetes).

A combined dataset of rDNA ITS and LSU sequences was used to infer the phylogenetic relationships of Hydnochaete peroxydata (≡ Hydnum peroxydatum), the type species of Hydnochaete. The species was retrieved nested within the Hymenochaete s. str. clade; therefore Hydnochaete is regarded as a synonym of Hymenochaete and the new combination Hymenochaete peroxydata is proposed.