Formation and regeneration of protoplasts from the ectomycorrhizal basidiomycete Laccaria bicolor

Protoplasts were released from dikaryotic mycelium of the ectomycorrhizal basidiomycete Laccaria bicolor using the lytic enzyme preparation NovoZyme 234. Protoplast release depended strongly on mycelium age, osmotic stabilizer, and temperature. The protoplasts could regenerate to form both monokaryotic and dikaryotic cultures capable of forming normal ectomycorrhizae with Pinus banksiana.

Breeding relationships among several species of Agaricus

We have examined the breeding behavior of several species of Agaricus including the cultivated A. brunnescens and the wild A. bitorquis, A. vaporarius, A. arvensis, A. campestris, A. silvicola, and A. placomyces. For A. brunnescens, two homo-karyons carrying auxotrophic mutations and compatible mating types were obtained from the American Type Culture Collection. A stable, prototrophic heterokaryon was recovered by nutritional selection from a pairing of the two auxotrophic strains. The two nuclear types were recovered from the heterokaryon by the formation and regeneration of protoplasts, many of which were homokaryotic. In A. bitorquis, a distinct macroscopic interaction correlated with dikaryon formation was observed in compatible matings of single-spore isolates. Fluffy zones of dikaryotic mycelium appeared in compatible pairings where the two cultures met. Mating among monosporous isolates was specified by unifactorial heterothallism. These observations of A. bitorquis were similar to those reported by others. Pairings of isolates from different stocks indicated a minimum of eight incompatibility alleles among 10 stocks of A. bitorquis. Although migration of nuclei generally does not occur in Agaricus, one stock of A. bitorquis produced monosporous isolates with nuclei that migrated through the resident mycelium of some compatible mates. The migration was evident as a fluffy zone of dikaryotic hyphae that spread unilaterally in a pairing. Monosporous isolates of A. vaporarius showed distinct mating interactions similar to those in A. bitorquis. No mating interactions were observed in pairings of sibling monosporous isolates of any of the other species examined. When isolates of different taxonomic species were paired, no reactions suggestive of compatibility were observed between A. brunnescens, A. bitorquis, A. vaporarius, or any of the other species.

Tilletia foetida. [Descriptions of Fungi and Bacteria].

A description is provided for Tilletia foetida. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Triticum, Secale, Triticale, Hordeum, Agropyron, Elymus, Sitanion, Lolium. DISEASE: Causes common bunt (stinking or covered smut) of wheat. Tilletia caries (CMI Descriptions 719) causes a virtually identical disease known by the same name. The seed contents inside the pericarp are converted to a mass of teliospores and the seed converted into a 'bunt ball' which ruptures on harvesting, releasing the black spores and the volatile compound trimethylamine which has a foul, fishy odour. Diseased plants are somewhat stunted and the heads of infected plants remain greener than those containing healthy grain and are more slender; the glumes of diseased spikelets are also spread apart. GEOGRAPHICAL DISTRIBUTION: Widely distributed in most countries where wheat is grown but less widespread than T. caries and not apparently in UK (CMI Map 295, ed. 2, 1968). TRANSMISSION: Spores are released when the grain is harvested and are dispersed by air to contaminate healthy grain and soil. Spores germinate in moist soil to produce a basidium and acicular basidiospores (primary sporidia). These fuse to produce a dikaryotic mycelium which may directly infect host seedling coleoptiles or produce further secondary sporidia.

Tilletia caries. [Descriptions of Fungi and Bacteria].

A description is provided for Tilletia caries[Tilletia tritici]. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Aegilops, Agropyron, Bromus, Elymus, Hordeum, Poa, Secale, Sitanion, Triticum, Triticale. DISEASE: Causes common bunt (stinking or covered smut) of wheat. Tilletia foetida (CMI Descriptions 720) causes a virtually identical disease known by the same name. The grain tissues inside the pericarp are converted to a mass of black teliospores producing a 'bunt ball' as the head matures. Diseased plants may be slightly stunted, infected ears ripen slower and the glumes project more than in healthy ears. Losses are caused both by direct loss of grain and by spoilage of grain and flour by contamination with the bunt spores which are released when the crop is harvested. Bunt spores release trimethylamine which has an odour of decaying fish. GEOGRAPHICAL DISTRIBUTION: Widespread, occurs in most countries where wheat is arown (CMI Map 294, ed. 3, 1978). TRANSMISSION: Spores are released when the grain is harvested and are dispersed by air to contaminate healthy grain and soil. Spores germinate in moist soil to produce a basidium and acicular basidiospores (primary sporidia). These fuse to produce a dikaryotic mycelium which may directly infect host seedling coleoptiles or produce further secondary sporidia.

Aspects infrastructuraux des altérations des anthères de Silene dioica parasitées par Ustilago violacea

The structural characteristics of the sporogenous and parietal tissues of healthy anthers of Silene dioica (L.) Clairv. (Caryophyllaceae) are described as well as those of anthers infected by Ustilago violacea (Pers.) Rouss. (Ustilaginales). In infected anthers, the invading dikaryotic mycelium grew intercellularly and very rarely penetrated the cells. The pathogen stopped stamen histogenesis at an early stage, causing necrosis specifically of the sporogenous tissue either directly or following hypertrophy. Five stages were distinguished during the histological modifications leading to anther destruction. (1) First, the mycelium developed in the anther filament and spread throughout the superficial tissues of the anther without causing histological changes in the anther. (2) Then, some sporogenous cells began to show necrosis and formed compact masses. (3) An increasing number of sporogenous cells became necrotic following strong vacuolisation and hypertrophy. (4) Hyphae grew profusely in the necrotic mass of sporogenic cells. (5) Finally, the fungus produced teliospores which filled the sporangial cavity.

Axenic culture of Cronartium fusiforme from three spore forms

Axenic cultures of the fusiform rust fungus (Cronartium fusiforme) were initiated from basidiospores, aeciospores, and uredospores. The morphology, cytology, and nuclear condition of the mycelium from the three spore stages are described and illustrated. Cultures derived from aeciospores and uredospores of C. fusiforme are reported for the first time. An improved culture medium is described. Inoculation of slash pine (Pinus elliottii var. elliottii) seedlings with suspensions of mycelium from basidiospores induced some typical galls which produced pycnial exudates and aeciospores. On synthetic medium, cultures from basidiospores were monokaryotic. Mostly dikaryotic mycelium was produced from aeciospores and uredospores, but some monokaryotic hyphae were observed.

Cultural Characters and Carpophore Constructi of Some Poroid Hymenomycetes^

The cultural characters and construction of the carpophores of 24 species of poroid Hymenomycetes were studied. The microstructures formed in culture and oxidase reactions of the cultures were compared with the microstructures present, the construction and type of decay of the carpophores from which they were made. Fhe type of interfertility of seven species was determined. Intercollection pairings of haploid mycelia derived from single basidiospores and the technique of dikaryotizing a large haploid mycelium growing in culture by pairing it with a small dikaryotic mycelium, were used to confirm the identity of different collections of eight different species. The literature on the classification, structure and anatomy of the carpophores and pure culture studies of Hymenomycetes. was reviewed. It was found that the 24 species were distributed among nine of the groups proposed by Nobles (1958) on the basis of their cultural characters. TTie structures formed in culture were also found to be present in the carpophores so that the carpophores could also be assigned to the some groups as their cultures. The carpophores did not indicate the same relationships as the cultures however. Differences in the micromorphological characters of hyphae and in the types of hyphae present in carpophores of species in the same group were found. Differences in construction of the carpophores were noticed in species with similar types of hyphae. Micromorphological characters of hyphae and the microstructures as well as the construction of the carpophores are constant for each species. Differences and similarity of micromorphological characters and construction of carpophores of different species are not adequately conveyed by the concept of hyphal systems.