Mycological Research News features : Straminipila, a new kingdom name for oomycete fungi; and Fungi from coral reefs (addendum).

This issue starts with a major review of fungal siderophores, and includes 12 other papers. Molecular papers address phylogeny and (or) infraspecific variation in Alternaria spp. (associated with apple core rot), Botrytis cinerea, Fusarium sp. (on lichens), Alternaria spp., Phaeoacremonium (including grapevine disease agent), Pycnoporus spp., and Verticillium fungicola, and, further heavily melanized variants of Gaemannomyces graminis var. tritici. Cell-wall polysaccharides show Cephalotheca to be polyphyletic in this feature.

Also investigated are the degradative properties of a lichenicolus Fusarium sp. zoospore and cyst membrance proteins in Phytophthora nicotianae, and phosphatase activities of an arbuscular mycorhizal fungus.

Revisions including keys are presented for Lichenostigma subgen. Lichenogramma (Arthoniales) and the British species of Tazzetta (Pezizales).

The following new scientific names are introduced: Lichenostigma diploiciae, L. epipolina, L. gracilis, L. rouxii and L. subradians spp. nov.; and Tazzetta scotica (syn. Pustularia scotica) comb. nov.

This issue of Mycological Research News features : Adhering to good cultural practice ; and Mycorrhizas of nonphotosynthetic plants.

Molecular phylogenetic papers in this part concern the position of microspordians in relation to fungi, Entyloma species, and Melampsora epitea populations. Mitochondrial plasmids in Cryphonectria parasitica populations are reported, and a PCR-method for detecting Rhizoctonia solani in soil is described. Incompatability tests and molecular methods address species concepts in the Heterobasidion insulare complex.

An extracellular protein from Colletotrichum coccodes which may be involved in pathogenicity is characterized. A low-cost scale-up method for the production of Clonostachys rosea is described, and Microsphaeropsis isolates with biocontrol potential are compared.

Oidiodendron maius is discovered to be a peat saprobe, not only an endophyte, and probably a Myxotrichum. Metal phosphate solubilization by Rhizoctonia solani has been investigated, as has salt tolerance in Aspergillus nidulans using mutant strains.

No new scientific names are introduced in this part of Mycological Research.

This issue of Mycological Research News features: New BMS website in action; How old are the fungi? Fourteen research papers are included. Molecular and experimental taxonomy papers address Psilocybe sect. Psilocybe, the affinities of Lepraria and Leproloma, variation in the bipolar Xanthoria elegans, the early detection of Tilletia tritici in wheat, repeated ITS1 sequences in a Nodulisporium, the cause of Cryphonectria canker on Tibouchina (Cryphonectria parasitica), variation in Beauveria bassiana isolates from different hosts (including the Coffee Berry Borer) and regions. Mating tests have been carried out to clarify the mating types in Ganoderma boninense, and to test species concepts in Polyporus s. str. species from South America.

The melanin biosynthesis pathway of various sapstain fungi has been identified, and protocols for the cryopreservation of Cantharellus cibarius developed.

Ecological papers examine the endophytes of Fagus sylvatica bark in the Apenines, the growth and development of entomogenous Alternaria alternata, fungi on moose dung from different habitats in Sweden, and the location of liquid water within two soil lichens.

No new scientific names are introduced in this part of Mycological Research.

A region of the nuclear ribosomal DNA containing the internal transcribed spacer 1 (ITS1), the 5·8S DNA and the internal transcribed spacer 2 (ITS2) was sequenced in 12 Polymyxa graminis and P. betae isolates, with particular emphasis on P. graminis from peanut clump-infested areas of the Indian subcontinent and West-Africa. Four different sequences were obtained from the seven isolates on sorghum or pearl millet, which differed from four sequences previously published for Polymyxa species and obtained for P. graminis isolates on barley, oat and wheat originating from temperate areas in Europe and America (two distinct sequences), for isolates on rice from Colombia and for P. betae isolates on sugar beet from several origins. The sequence variations concerned mainly the composition and length of ITS1 and ITS2 regions. Phylogenetic trees built with the distinct sequences currently known for Polymyxa spp. using parsimony, maximum likelihood and neighbour-joining methods separated P. betae from P. graminis. Within P. graminis, the hierarchy of the clustering partially matched the host range and geographical origin of the isolates. These results confirm the great diversity within P. graminis that has already been observed in host range and temperature requirements studies, and provide new arguments for considering several taxa within the species. On the basis of the ecological requirements and rDNA sequences of distinct P. graminis isolates, five special forms are proposed: P. graminis f. sp. temperata, P. graminis f. sp. tepida, P. graminis f. sp. subtropicalis, P. graminis f. sp. tropicalis and P. graminis f. sp. colombiana.

In April, Mycological Research News drew attention to two studies on the fungi isolated from coral reefs (Mycological Research106(4): 387, April 2002). Both found that fungi generally encountered in terrestrial environments predominated, and that while numerous isolates could be obtained, the number of species present was somewhat limited. It is always easier to discover something than to find if it has been discovered before. In this case, neither paper mentioned a fascinating study by Kendrick et al. (1982) which investigated fungi from the interior or living corals with a view to identifying ones that might be involved in their bioerosion. These authors discovered 18 species, again mainly from ‘terrestrial’ genera such as Aspergillus, Cladopsorium, and Penicilliu. Further, they demonstrated the presence of microborings attributed to fungal hyphae in the aragonite coral skeletons by light and scanning electron microscopy following plastic infiltration; that the borings were of fungal origin was confirmed by reinoculating samples of the coral Siderastrea siderea with A. versicolor and P. stoloniferum and reproducing the phenomenon in the laboratory. The extent to which such fungi are involved in coral declines, either as causal agents or secondary invaders appears to be a fascinating area for further study, particularly as bacteria rather than fungi have received most attention in relation to coral reef health (Santavy 1995).

PCR and DNA sequence analysis have become standard tools for identification, detection and phylogenetic analysis of fungi. A large number of species are incapable of growth in the laboratory, making the preparation of pure DNA problematical. The amplification of DNA samples from impure material is subject to misinterpretation if more than one species is present. To overcome this problem, we designed an in situ PCR technique that links PCR amplification to the light microscopic image. The amplified tissue is stained, thus confirming which morphotype has been amplified. The PCR product can then be sequenced. We tested the technique on fixed Blumeria graminis spores and mycelia using primers derived from the sequence of the gene encoding the catalytic subunit of protein kinase A (bka1). This is the first report of in situ PCR on phytopathogenic fungal material. This technique allows positive confirmation of the origin of genes cloned from obligate pathogenic fungi and could be adapted for use on any samples containing mixed fungal species.

Microsporidia are intracellular parasitic microbes, which were once thought to be among early diverging eukaryotes, mainly because they lack mitochondria. However, this evolutionary scheme has been challenged by protein-based molecular phylogenetic studies, which suggest a more recent origin of the Microsporidia, which clustered Microsporidia with or within ‘true’ fungal lineages. However, most of these studies did not include sequences from basal fungal phyla (Chytridiomycota and Zygomycota), and unrepresentative taxon sampling could have resulted in misleading relationships being suggested. To further investigate the evolutionary origin of Microsporidia relative to Fungi, we performed molecular phylogenetic analyses with newly determined RPB1 (DNA-dependent RNA polymerase II largest subunit) and EF-1α (translation elongation factor I alpha) including sequences from basal fungi. Although the phylogenetic position of Microsporidia in the EF-1α tree still might be misplaced due to the unusually high rate of sequence divergence of the microsporidian EF-1α gene, the phylogenies recovered based on these two protein sequences do not provide strong evidences for a close relationship between Microsporidia and Fungi. Moreover, we have identified within the EF-1α genes a characteristic two amino acid deletion conserved in all fungal sequences currently available, whereas this deletion is absent in microsporidian sequences. These results argue against the view of Microsporidia as highly degenerate fungi, and whether Microsporidia and Fungi are sister taxa remains unresolved.

Ecologically important ectomycorrhizal (EM) associations are poorly known from equatorial rain forests of South America. Recent field studies in the Pakaraima Mountains of western Guyana revealed previously undocumented forests dominated by EM leguminous trees, with a rich assemblage of EM mycobionts. Along transects, basidiomes from 75 species or morphospecies of putatively EM fungi were spatially associated with leguminous host trees. These fungi belonged to the basidiomycete families Boletaceae, Amanitaceae, Russulaceae, Cortinariaceae, Cantharellaceae, Clavulinaceae, and Entolomataceae, all of which are poorly documented from the lowland neotropics. Ectomycorrhizas were confirmed on D. corymbosa, D. altsonii, and D. jenmanii (Caesalpiniaceae, tribe Amherstieae), and a fourth species, Aldina insignis (Papilionaceae). The tribe Amherstieae contains most of the EM leguminous species forming monodominant forests in Guineo-Congolian Africa. Dicymbe species constituted the first record of EM Amherstieae in the New World. A variety of other co-occurring caesalpiniaceous trees failed to exhibit ectomycorrhizas. Transect surveys indicated that D. corymbosa and D. altsonii were: (1) highly clumped and dominant at specific sites; (2) occurred on soils with widely varying chemical and textural characteristics; and (3) the most important hosts for EM fungi in the local landscape. Dicymbe species have life history attributes, including the ectomycorrhizal habit, which enhance their competitive abilities irrespective of soil conditions. The spatial restriction of EM fungal basidiomes indicated that discrete groves of EM trees harbour an important component of regional macromycete diversity.

Siderophores are low molecular weight, iron-chelating ligands produced by nearly all microorganisms. Fungi synthesize a wide range of hydroxamate siderophores. This review considers the chemical and biological aspects of these siderophores, their distribution amongst fungal genera and their possible applications. Siderophores function primarily as iron transport compounds. Expression of siderophore biosynthesis and the uptake systems is regulated by internal iron concentrations. Transport of siderophores is an energy-dependent process and is stereoselective, depending on recognition of the metal ion coordination geometry. In addition to transporting iron, siderophores have other functions and effects, including enhancing pathogenicity, acting as intracellular iron storage compounds and suppressing growth of other microorganisms. Siderophores can complex other metals apart from iron, in particular the actinides. Because of their metal-binding ability there are potential applications for siderophores in medicine, reprocessing of nuclear fuel, remediation of metal-contaminated sites and the treatment of industrial waste.