Ectomycorrhizal Amanita Research Articles

Death caps (Amanita phalloides) frequently establish from sexual spores, but individuals can grow large and live for more than a decade in invaded forests.

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.

Comparative Mitogenome Analysis Reveals Mitochondrial Genome Differentiation in Ectomycorrhizal and Asymbiotic Amanita Species.

In this present study, we assembled and analyzed the mitogenomes of two asymbiotic and six ectomycorrhizal Amanita species based on next-generation sequencing data. The size of the eight Amanita mitogenomes ranged from 37,341 to 137,428 bp, and we considered introns to be one of the main factors contributing to the size variation of Amanita. The introns of the cox1 gene experienced frequent gain/loss events in Amanita; and the intron position class cox1P386 was lost in the six ectomycorrhizal Amanita species. In addition, ectomycorrhizal Amanita species had more repetitive sequences and fewer intergenic sequences than asymbiotic Amanita species in their mitogenomes. Large-scale gene rearrangements were detected in the Amanita species we tested, including gene displacements and inversions. On the basis of the combined mitochondrial gene set, we reconstructed the phylogenetic relationships of 66 Basidiomycetes. The six ectomycorrhizal Amanita species were of single origin, and the two saprophytic Amanita species formed two distinct clades. This study is the first to elucidate the functions of the mitogenome in the evolution and ecological adaptation of Amanita species.

In and out of refugia: historical patterns of diversity and demography in the North American Caesar's mushroom species complex.

Some of the effects of past climate dynamics on plant and animal diversity make-up have been relatively well studied, but to less extent in fungi. Pleistocene refugia are thought to harbour high biological diversity (i.e. phylogenetic lineages and genetic diversity), mainly as a product of increased reproductive isolation and allele conservation. In addition, high extinction rates and genetic erosion are expected in previously glaciated regions. Some of the consequences of past climate dynamics might involve changes in range and population size that can result in divergence and incipient or cryptic speciation. Many of these dynamic processes and patterns can be inferred through phylogenetic and coalescent methods. In this study, we first delimit species within a group of closely related edible ectomycorrhizal Amanita from North America (the American Caesar's mushrooms species complex) using multilocus coalescent-based approaches; and then address questions related to effects of Pleistocene climate change on the diversity and genetics of the group. Our study includes extensive geographical sampling throughout the distribution range, and DNA sequences from three nuclear protein-coding genes. Results reveal cryptic diversity and high speciation rates in refugia. Population sizes and expansions seem to be larger at midrange latitudes (Mexican highlands and SE USA). Range shifts are proportional to population size expansions, which were overall more common during the Pleistocene. This study documents responses to past climate change in fungi and also highlights the applicability of the multispecies coalescent in comparative phylogeographical analyses and diversity assessments that include ancestral species.

Macrofungi in the lateritic scrub jungles of southwestern India

A pilot study on macrofungi in scrub jungles (with and without fire-impact) in lateritic region of southwestern coast of India was carried out. Out of 11 species in 10 genera recovered, six and five species were confined to scrub jungle and fire-impacted scrub jungle, respectively. An ectomycorrhizal Amanita sp. was the most frequent in scrub jungle associated with exotic ( Acacia auriculiformis and A. mangium ) and plantation ( Anacardium occidentale ) trees. Based on traditional knowledge, it is a highly edible and nutritional delicacy in the coastal regions. Astraeus odoratus was another common ectomycorrhizal fungus in native trees Hopea ponga , which was recovered from the fire-impacted scrub jungle and is possibly edible. Edible termite mound mushroom Termitomyces striatus was also common in the fire-impacted scrub jungle. Chlorophyllum molybdites was the most frequent mushroom in the fire-impacted scrub jungle.

Morphological and Molecular Characterization of Ectomycorrhizal Amanita Species Associated with Pinus wallichiana A. B. Jacks.

Worldwide genus Amanita is represented by more than 500 ectomycorrhizal (ECM) species. These species form mutualistic associations with a number of host trees among which the conifers predominate. Set out to explore the ECM associations of Amanita in Kashmir Himalayas, Amanita calyptroderma, Amanita pantherina and Amanita vaginata show symbiotic associations with the roots of Pinus wallichiana. Besides morphological characterization of mycorrhizal roots and sporocarps, molecular characterization of rDNA ITS region was performed for identification of species. ITS-rDNA was used for molecular analysis. The target region of rDNA was amplified using universal fungal primers (ITS1 and ITS4). The sequencing of amplified products and their subsequent blast analysis confirmed the identification of species by comparing the sequences of these species with sequences present in GenBank. Phylogenetic analysis also confirmed the identification of species.