This issue of Mycologcal Research News features: Locust and grasshopper control with fungi.

Fifteen papers are included in this part. Nutrient use of mycorrhizal and saprotrophic fungi is compared; Spathulospora is shown by molecular methods to belong to the Sordariomycetes; and novel anamorphs belonging to two Tuber species have been discovered in soil.

Molecular phylogenetic studies around the species level consider: the Ophiostoma minus group; variation in Entoleuca mammata; the placement of Rhynchosporium alismatis in Plectosporium; the identity of Hygrophorus cossus based on sequences from 200 yr old specimens; the differentiation of two special forms in Fusarium oxysporum; and a new crop-associated species of Pythium in North America.

Volatile organic compounds produced by two wood-rotting fungi are characterised and detection methods compared; and a procedure for the more rapid production of gametangia and so the typing of races of Phytophthora ramorum is reported.

The infection processes in the plant pathogenic Helminthosporium solani and the potential biocontrol agent Plectosporium alismatis are documented in detail, and a new rust on Kalanchoe cultivars has been discovered.

The following new scientific names are introduced: Aecidium kalanchoe, and Pythium attrantheridium sp. nov.; and Plectosporium alismatis (syn. Septoria alismatis) comb. nov.

Whole genome sequencing of several filamentous ascomycetes is complete or in progress; these species, such as Aspergillus nidulans, are relatives of Saccharomyces cerevisiae. However, their genomes are much larger and their gene structure more complex, with genes often containing multiple introns. Automated annotation programs can quickly identify open reading frames for hypothetical genes, many of which will be conserved across large evolutionary distances, but further information is required to confirm functional assignments. We describe a comparative and functional genomics approach using sequence alignments and gene expression data to predict the function of Aspergillus nidulans genes. By highlighting examples of discrepancies between the automated genome annotation and cDNA or EST sequencing, we demonstrate that the greater complexity of gene structure in filamentous fungi demands independent data on gene expression and the gene sequence be used to make confident functional assignments.

Stable isotopes in fruit bodies from field studies have been used to infer ectomycorrhizal or saprotrophic status and to understand carbon and nitrogen use, but few controlled culture studies have correlated source and fungal isotopic patterns. Here, we measured natural abundances of 15N and 13C in ten strains of ectomycorrhizal fungi and seven strains of saprotrophic fungi grown on agar with three different primary carbon sources: glucose, glucose plus malt extract, and potato dextrose agar. Eight fungal strains were also grown using position-specific, 13C-labelled glucose (C-1 through C-6 labelled). Most fungi resembled nitrogen sources in δ15N, suggesting that growth on agar media minimizes isotopic fractionation on uptake compared to growth on liquid media, and that in general saprotrophic and mycorrhizal fungi process nitrogen similarly. Saprotrophic fungi were more depleted in 13C than ectomycorrhizal fungi on all media, presumably because of assimilation of 13C-depleted, agar-derived carbon. Results on 13C-enriched glucose indicated that saprotrophic fungi obtained up to 45% of their carbon from the agar substrate. Fungi generally incorporated the individual carbon atoms of glucose in the order, C-4<C-1<C-2, C-3, C-5<C-6, ranging from a mean of 9% for the C-4 atom to 21% for the C-6 atom. Based on these incorporation patterns and intramolecular 13C patterns within glucose, differential incorporation of carbon atoms within glucose among fungal taxa contributed less than 1‰ to isotopic differences among taxa, whereas isotopic fractionation among taxa during metabolism varied up to 4‰. Parallel studies of 13C-enriched and natural abundance substrates were crucial to interpreting our results.

The zygomycete Phycomyces blakesleeanus has a 30 Mb genome with a 35% content of guanine and cytosine (GC). We determined the GC content in Phycomyces genes and fragments of genes available in public databases, the frequency of nucleotides in each codon position, and the codon usage. We observed a difference of 18% between the GC content of protein-coding and non-coding DNA. This large difference allowed the visualization of protein-coding DNA by plotting the GC content along a segment of Phycomyces DNA. We have identified a high GC DNA segment linked to the pyrG genes of the zygomycete genera Phycomyces, Mucor, and Blakeslea that corresponds to the 3′ end of the gene responsible for the protein kinase C.

The phylogenetic position of the marine ascomycete genus Spathulospora was investigated using partial SSU and LSU DNA sequences obtained from dried herbarium specimens. Spathulospora was represented by the two species S. adelpha and S. antarctica. Phylogenetic analyses using Bayesian, parsimony, and neighbour-joining algorithms on SSU and LSU data sets agreed with the placement of Spathulospora. Both Spathulospora species are each others closest relatives, and group within the Lulworthiales (Sordariomycetes, Ascomycota) with support in all analyses. Members of the morphologically similar insect parasites in the Laboulbeniomycetes are not closely related to Spathulospora. Despite several striking morphological differences between Spathulospora and Lulworthiales, an important shared morphological character was found that until now had not been recognized. Ascospores of Spathulospora and some members of the Lulworthiales have apical chambers containing mucus believed to be involved in ascospore attachment. A closest relative to Spathulospora could not be determined.

The family Porinaceae (Trichotheliales) is characterized by perithecial ascomata of ascohymenial origin. The phylogenetic position of this family in the system of ascomycetes has been uncertain and is investigated using mtSSU rDNA sequences. The dataset consists of lichenized representatives of major ascomycete lineages, including those that were previously suspected as relatives of Porinaceae, such as Pyrenulaceae. The dataset was subjected to a Bayesian phylogenetic analysis implementing a Metropolis Coupled Markov Chain Monte Carlo method. The analysis confirms previous classification of the apothecial Gomphillaceae near to Graphidaceae, and suggests that the pyrenocarpous Porinaceae are also close to Graphidaceae, Gyalectaceae, and Stictidaceae. The subclass Ostropomycetidae is here suggested to include the families Gomphillaceae, Gyalectaceae, Graphidaceae (incl. Thelotremataceae), Porinaceae, and Stictidaceae. A special type of hemiangiocarpous ontogeny of the ascomata is shared throughout the Ostropomycetidae, and the closed fruit bodies of Porinaceae are apparently a result of a neotenic ontogeny. This is associated with special hymenial characters: rather thin-walled narrow asci, and a different consistency of the hymenial gels.