Twenty-one isolates of the nematode-vectored plant pathogen, Dilophospora alopecuri, were examined by allozyme electrophoresis. The study focused on isolates from Australia, including those associated with populations of the seed-gall nematode, Anguina funesta, in Western Australia (W.A.), where the fungus apparently provides natural control of the A. funesta–Clavibacter toxicus association responsible for annual ryegrass toxicity, and a range of Anguina populations in south-eastern Australia. Reference strains from international culture collections were included. Variation was found in 26 of 27 presumptive loci and 10 electrophoretic types were identified. All Australian isolates fell into six electrophoretic types that formed two groups of three that differed by less than 13% within each group, but differed by over 70% between the groups. Of the isolates from W.A., six fell into one electrophoretic type and one into a second electrophoretic type that differed at one locus only. Three exotic isolates varied from Australian ones by 27–74%. Dilophospora alopecuri exhibited greater within-species allelic variation than previously reported for asexually-reproducing halophase fungi. The lack of variation within W.A. suggests that (i) a teleomorph does not occur under local conditions, (ii) the W.A. population has arisen from a single introduction and (iii) selection of strains suitable for biocontrol of Anguina funesta and Clavibacter toxicus should include material from eastern Australia.

The possibility that the Coemansia spiralis complex contains three species is discussed on the basis of six descriptions. The name C. spiralis is retained for the fungus first described with the appropriate generic placement and incorporates C. nantahalensis. The second species, for which preserved material is not available, is named as C. bainieri nom. nov., and C. linderi sp. nov. is the third species.

The capacities of 24 decay fungi, isolated from living trees and decayed timber of the East African camphor tree, to colonise sapwood and heartwood of living trees was tested. Eight species colonised sapwood, and five colonised heartwood and were viable 12 months after inoculation. It was noteworthy that eight important decay species of the East African camphor timber, including Phellinus senex, which is the dominant heartrot species, failed to invade tissues of living trees. The implications of these findings are discussed in relation to the water content and pH of infected and non-infected tissues as well as some parameters of growth of colonised trees.

Two new coelomycetes with appendaged conidia collected on branches of Eucalyptus species in Tasmania are described, illustrated and compared with closely related taxa. They are Ciliosporella tuberculiformis sp. nov. on E. regnans and Neoplaconema cymbiforme sp. nov. on E. nitens.

Dicellomyces calami sp. nov. was collected on rotang palm in southern India. It is the first Dicellomyces species on palms. A key to the known Dicellomyces species is presented and possible relationships of the genus are discussed.

This issue of Mycological Research News features: Electronic manuscript submission and tracking; and Sex and stress in soil fungi.

Fifteen papers are presented. Molecular papers concern sebacinoid ectomycorrhizal fungi, relationships of the daisy rust Puccinia distincta, variability in Crinipellis perniciosa, the VCP1 protease in Pochonia chlamydosporia, and Venturia on poplars in the Pacific north-west.

The interactions of nematophagous fungi are explored, the effects of the mycoparasite Sphaerellopsis filum on Melampsora larici-epitea studied, and the action of mycoparasites on Sphaerotheca fusca examined. Effects of sugars on Tuber borchii mycelial growth are compared, and the dispersal role of cage-like ascomatal peridia is documented.

Taxonomic papers are concerned with Parmulariaceae, tropical polypores, and the lichenized hyphomycete genus Cheiromycina. In addition, four fossil fungi are described from amber deposits: three coelomycetes and the earliest report of a myxogastroid slime mould.

New scientific names introduced in this part are: Asteromites, Leptostromites, Leptothyrites, Mintera, Perenniporiella, and Viegasella gens. nov.; Arcyria sulcata, Asteromites mexicanus, Cheiromycina ananas, C. globosa, Leptostromites ellipticus, Leptothyrites dominicanus, P. pendula, and Venturia inopina spp. nov.; M. reticulata (syn. Parmularia reticulata), P. micropora (syn. Perenniporia micropora), P. neofulva (syn. Polyporus neofulvus), and Viegasolla pulchella (syn. Schneepia pulchella) combs.nov.

Six new species of Puccinia on Baccharis are described: Puccinia basirostrata, P. ecuadorientalis, P. lentapiculata, P. otavalensis and P. quitensis from Ecuador, and P. vulcanicola from Costa Rica. Beside features of telio-, uredinio- and aeciospores, basidiospore morphology yielded important characters for species delimitation.

Records of the Piptocephalidaceae and Chaetocladiaceae from over 800 samples of dung collected worldwide are analysed. Piptocephalis species were frequent, occurring especially on dung of rabbit (31% of all samples) in temperate regions. Chaetocladium and Syncephalis species were much less frequent. The status of these fungi as coprophils and reasons for the differences in distribution and substrate preference are discussed.

The mode of hyphal interaction and parasitism of Coemansia spp., mainly C. aciculifera and C. thaxteri, by Gliocladium roseum, Fusarium flocciferum and Verticillium psalliotae, species that occurred with the Coemansia spp. in wheat rhizospheres, was observed in mixed cultures on low nutrient medium. Two types of interaction occurred. G. roseum and F. flocciferum coiled round, penetrated and grew within the host's hyphae. V. psalliotae grew parallel to and along the host's hyphae, coiling only rarely, and sometimes formed thick mycelial layers on the host's sporangiophores. After infection by each fungus, the host's hyphae became narrower, collapsed and then disintegrated. The observations suggest parasitism followed by lysis rather than the involvement of antibiotics.

Developmental stages in mitospore production in Pseudocercospora musae were examined by differential interference contrast light microscopy, scanning electron microscopy, and transmission electron microscopy. Mitosporogenous cells consistently originated directly from upper stromatic cells. Concentric bodies were found in both stromatic and mitosporogenous cells. The cell wall of stromatic cells, mitosporogenous cells, and mitospores, consisted of two layers. Mitospore ontogeny was found to be holoblastic and mitospore secession schizolytic. After liberation, the mitosporogenous cell apex and the mitospore base exhibited a half septum consisting of one layer. A central pore, occluded by a Woronin body, was observed in the mitosporogenous locus. Mitosporogenous cells proliferated percurrently. The morphological characteristics of the apex of mitosporogenous cells and the base of liberated mitospores in P. musae is of fundamental value in defining unthickened scars as important criteria for generic separation within the Cercospora-like generic assemblage.

Hirsutella petchabunensis is described from a single specimen collected on a Lepidoptera larva in tropical forest in Thailand. This is linked, both in the field and through cultural studies, with a distinctive helicosporous synanamorph that is assigned to Helicoma.

The cyclic tetrapeptide, HC-toxin, is a host-selective virulence determinant produced by the foliar pathogen of maize, Cochliobolus carbonum race 1. HC-toxin is synthesized by a multifunctional peptide synthetase (HTS) encoded by the HTS1 gene. Analyses of culture filtrates identified low toxin-producing and high toxin-producing strains among field isolates of the pathogen. These strains were analyzed by reverse transcription PCR to determine whether synthesis of the toxin is directly influenced by HTS1 transcript levels. The results indicated that expression of HTS1 was up-regulated and reached maximal levels several days before the toxin was detected in the culture medium and that HTS1 transcript levels were not correlated with toxigenicity. These observations suggest that genes in addition to HTS1 are involved in regulation of HC-toxin biosynthesis. The toxin-producing ability of low toxin-producing isolates was enhanced following inoculation and reisolation from leaves of susceptible maize genotypes, suggesting that additional factors within the host environment influence toxin production during pathogenesis.

Monilinia fructigena secretes one molecular form of endo-polygalacturonase (PG) in apple fruits infected by it. This PG, purified from culture filtrate to homogeneity, had an Mr of ca 33000 (SDS electrophoresis) and a pI value of ca 9·75. It had little or no effect on the structural integrity of potato tuber tissues, nor on the viability of apple callus cells in suspension. Modification of the lysine units of the purified enzyme by pyridoxal phosphate resulted in ca 50% decrease in PG activity. PG thus modified appeared to bind to an apple fibre preparation less than did PG not treated with pyridoxal phosphate. Lysine residues may thus be involved in subsites binding this PG to carboxyl groups in the polygalacturonate.

The action of high concentrations of benomyl was investigated in the wild-type strain St Lawrence of Neurospora crassa and in mutants displaying various levels of tolerance to the drug. Germ-tube formation by macroconidia, germination pattern (single versus multiple germ-tube emergence) and hyphal tip extension of these strains showed different sensitivities to the microtubule inhibitor, benomyl. The wild-type strain, whose vegetative growth was inhibited at micromolar concentrations, still germinated by multipolar outgrowth at 100 μm. At such a level, germination of the moderately resistant mutant Bml 511(r) was inhibited more than the wild type. Highly resistant mutants capable of hyphal growth at 500 μm were obtained by mutating strain Bml 511(r) using uv. One of these, strain E1-91, showed temporary sensitivity to the microtubule inhibitor and produced multiple germ-tubes. This strain was deficient in the β-tubulin polypeptide during the first hour of germination.

A new species of Ramulispora, R. cerealis sp. nov., isolated from the stem base of a barley plant, is described.

The production of basidia from individual teliospores of Sporisorium formosanum and Ustilago affinis is described. In S. formosanum the upper portion of the basidium separates as a conidium-like body the two cells of which either conjugate or produce sporidia, whilst the lower portion remains unicellular and gives rise to sporidia. In U. affinis the basidium is four-celled and remains intact, its cells either conjugating or producing sporidia, sometimes on the same basidium. These patterns of teliospore germination are compared with one another and other members of the Ustilaginaceae, notably Ustilago trichophora.