Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

Climate change 2014 - Synthesis Report

The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third-party annotation effort. We introduce the term ‘species hypothesis’ (SH) for the taxa discovered in clustering on different similarity thresholds (97–99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web-based sequence management system in UNITE.

http://web.stanford.edu/~kpeay/papers/Koljalg_2013_MEC.pdf

Towards a unified paradigm for sequence-based identification of fungi

Publisher Summary In this chapter, the advances that have been made in understanding the ecology of the mineral nutrition of wild plants from terrestrial ecosystems have been reviewed. This chapter is organized along three lines. First, the issues of nutrient-limited plant growth and nutrient uptake, with special emphasis on the importance of the uptake of nutrients in organic form—both by mycorrhizal and by non-mycorrhizal plants—and the importance of symbiotic nitrogen fixation is treated. In addition, the influence of allocation patterns on mineral nutrient uptake is described. Next, a few of the nutritional aspects of leaf functioning and how nutrients are used for biomass production by the plant are explored. That is done by studying the nutrient use efficiency (NUE) of plants and the various components of NUE. Finally, the feedback of plant species to soil nutrient availability by reviewing patterns in litter decomposition and nutrient mineralization is investigated. The chapter concludes with a synthesis of the various aspects of the mineral nutrition of wild plants. The chapter ends with a conceptual description of plant strategies with respect to mineral nutrition.

The Mineral Nutrition of Wild Plants Revisited: A Re-evaluation of Processes and Patterns

Fungi play major roles in ecosystem processes, but the determinants of fungal diversity and biogeographic patterns remain poorly understood. Using DNA metabarcoding data from hundreds of globally distributed soil samples, we demonstrate that fungal richness is decoupled from plant diversity. The plant-to-fungus richness ratio declines exponentially toward the poles. Climatic factors, followed by edaphic and spatial variables, constitute the best predictors of fungal richness and community composition at the global scale. Fungi show similar latitudinal diversity gradients to other organisms, with several notable exceptions. These findings advance our understanding of global fungal diversity patterns and permit integration of fungi into a general macroecological framework.

/pdf/global-diversity-and-geography-of-soil-fungi-opxv1vryce.pdf

Global diversity and geography of soil fungi

A reassessment of the taxonomy of some tropical sooty moulds.

Lichens of tropical forests.

Given that changes in the patterns of vegetation and size of carbon (C) pools in the Arctic are likely to be profound by the end of this century, it is necessary to characterise the identity and ecological groupings, in terms of temperature response and C substrate utilisation, of saprotrophic (decomposer) fungi in organic matter in Arctic soils. Thus, the aims of this study were: (1) to identify the fungi isolated from standing-dead material of Schistidium apocarpum , as an example of a High Arctic moss, (2) to determine mycelial extension rates of these fungi at a range of temperatures (4, 10 and 25 °C), and (3) to characterise the functional potential, defined by C substrate utilisation at 6 °C, of fungal taxa. Fungi were isolated at 4 °C from standing-dead material of S. apocarpum from an area of polar semi-desert (79 degrees N), close to Ny-Alesund, Svalbard, in the High Arctic. From a collection of 662 isolates, 43 pure cultures were identified by DNA extraction, amplification, and sequencing. Phoma sclerotioides , previously known as a temperate snow mould, was isolated most frequently. The ecology of fifteen fungal isolates was characterised in detail. In terms of temperature response, two groups were apparent, one of truly psychrophilic/psychrotrophic fungi and one of more mesophilic fungi which were generally less frequently isolated. In terms of carbon substrate utilisation in semi-defined solid media, most fungi could utilise a variety of carbon substrates (degradation of casein, cellulose and starch was widespread), except for tannic acid (degraded by only two of the five P. sclerotioides isolates and Scytalidium lignicola ) and lignin and chitin (not decomposed by any isolate). The majority of isolates had been recorded previously from polar environments and/or as being able to survive at low temperatures. Fungi in tundra ecosystems, therefore, have significant potential to mineralise C at temperatures below 10 °C. A better understanding of the ecology of these fungi will allow us to improve predictions of C dynamics in arctic biomes in the future.

Clare H. Robinson

Papers

A reassessment of the taxonomy of some tropical sooty moulds.

Lichens of tropical forests.

Characterisation of cold-tolerant fungi from a decomposing High Arctic moss

Tropical Mycology: Volume 1, Macromycetes

Mushroom collection in Tanzania and Hunan (Southern China): inherited wisdom and folklore of two different cultures.