Lepista Nuda Research Articles

Breeding of edible fungi with emphasis on the variability among French genetic resources ofAgaricus bisporus

Our laboratory (INRA) has developed breeding programs for several species of edible fungi. For example, "sporeless" strains were obtained by mutagenesis for Pleurotus ostreatus and Pleurotus pulmonarius, a hybrid strain of Lepista nuda has been marketed, and genetic variability has been studied in Tuber melanosporum. At present, the largest program concerns Agaricus bisporus, for which a collection of about 200 French isolates from 44 sites has been gathered. High genetic polymorphism appeared even within each site. Nine genetically different isolates from the same site were studied in experimental culture. Variability was observed for color of the cap, susceptibility to bacterial blotch, and the elevated basidial spore number trait. A single isolate, Bs 261, gave sporocarps having a majority of tetrasporic basidia, and spores which, for the most part, were homokaryotic. This strain was interfertile with typical bisporic strains. The resulting hybrids were either bisporic or tetrasporic, according to which homokaryon of Bs 261 was used. More investigations will be necessary to understand the presence of a rare tetrasporic strain in a bisporic population and also to study the relationship between Bs 261 and the tetrasporic strains of the previously described A. bisporus var. burnettii. Key words: edible fungi, Agaricus bisporus, genetic resources, breeding, basidial spore number, tetrasporic trait.

Silver content of wild-grown mushrooms from Northern Poland

Wild-grown and mostly edible species of higher mushrooms collected in 1989-1992 from the districts of Gdańsk, Elblag and Piła (northern part of Poland) have been investigated with regard to their silver content. In total, 527 samples including 25 mushroom species of six families (Agaricaceae, Boletaceae, Cantharellaceae, Hygrophoraceae, Coprinaceae and Russulaceae) were examined. Among the fungi examined only Agaricus campestris and A. augustus were heavy bioaccumulating species and showed the highest concentrations of 35 mg Ag/kg dry weight (1.1-150) and 2.0-6.9 mg/kg, respectively. Silver concentrations exceeding 1.0 mg/kg dry weight were noted in Boletus aestivalis, Lepista nuda, L. personata, and in some specimens of B. edulis, Leccinum scrabum, L. vulpinum, Cantharellus cibarius and Coprinus comatus.

Concentrations of lead, cadmium, mercury and copper in mushrooms in the vicinity of a lead smelter

The concentrations of four heavy metals in 149 samples of mushroom fruiting bodies representing 11 species, mainly all edible, were determined by atomic absorption spectroscopy. The mushrooms were collected up to a distance of 6 km from a lead smelter in central Bohemia (Czechoslovakia) in operation since 1786. Lead was accumulated extensively by Lepiota rhacodes and Lepista nuda. Among other species, significant accumulation was found up to a distance of 1 km from the source. Concentrations of > 100 mg kg −1 dry matter were often determined. The safe limit of 5 mg kg −1 dry matter was exceeded in most samples collected at distances of up to 6 km from the source. Concentrations of cadmium in the polluted area were generally significantly higher than in other parts of Bohemia. Cadmium was extensively accumulated by the toxic Amanita muscaria, but also by the edible Boletus edulis and Amanita rubescens, with mean values 28.6, 15.2 and 12.3 mg Cd kg −1 dry matter, respectively. The Czechoslovakian statutory limit is 0.5 mg Cd kg −1 dry matter. Statistically significant linear correlations between lead and cadmium concentrations were found only for Boletus edulis and Paxillus involutus. Mercury was accumulated by Lepista nuda and Lepiota rhacodes; mean values of 11.9 and 6.5 mg Hg kg −1 dry matter, respectively, were found. Concentrations of mercury in most species from the study area were higher than in those from other parts of Bohemia. Lepiota rhacodes and Lepista nuda also accumulated copper extensively with mean values of 280 and 193 mg Cu kg −1 dry matter, respectively.

Microcolonies of bacteria as a nutrient source for lignicolous and other fungi

Under low nutrient conditions hyphae of certain fungi are strongly attracted to microcolonies of bacteria belonging to the genera Pseudomonas and Agrobacterium. Hyphae of the fungi penetrate the microcolonies and proliferate to produce coral-loid, haustorial-like masses of absorptive hyphae. The bacteria in the colonies are lysed and the contents apparently absorbed as a nutrient source by the fungi. The four fungi that demonstrated this capability were Agaricus brunnescens (= A. bisporus), Coprinus quadrifidus, Lepista nuda, and Pleurotus ostreatus. Approximately 100 additional species belonging to the Basidiomycota, Oomycota, Zygomycota, Deuteromycota, or Ascomycota were also tested, but none were found capable of attacking and digesting bacterial colonies in this way.

Influence of natural turfs and sods of single crop plants on mycelial development of three basidiomycetous ground fungi, preferentially associated with grassland

Mycelia of three basidiomycetous ground fungi, preferentially associated with grassland ecosystems, were inserted in the untreated soil of 2-1 glass jars. Natural turf pieces and artificial single-plant sods were brought into direct or indirect contact with the inoculated soil substrate to simulate the conditions of the edaphosphere of herbaceous plants to the fungal mycelia. With the exception of certain leguminous crops whose rhizosphere is highly stimulatory, all kinds of sods grafted on the edaphosphere soil served predominantly as a cover that limits the outflow of inhibitory volatiles, produced in the soil itself. With some exceptions, mycelial development was neither stimulated by the possibility of profiting exudates of the plant rhizosphere nor by volatile exhalations released from the sods. It is concluded that mycelial growth in edaphosphere soils is inhibited by restricted exchange of gaseous metabolites, arising from the soil itself, and by volatiles from the plant population and its decaying residues, among which carbon dioxide and substances, released from dead plant material, appear to be most effective. In addition, the fairy-ring fungus, Lepista nuda, proved to be a facultative necrotrophe to climatically weakened herbs with a poor utilization of the subjacent soil, whereas Agaricus porphyrizon and Agrocybe praecox utilized the subjacent soil with a certain preference to dead plant residues. Their pretended association with herbs is caused in the stimulation of fruiting, but not in mycelial growth, by the crop plants accompanied. Die Myzelien von drei bodenbewohnenden Basidiomyceten, die vorzugsweise mit Grasland assoziiert sind, wurden in die unbehandelte Erde von 2-1 Glasgefäßen eingesetzt. Natürliche Rasenstücke und angesäte Rasen mit einer einzelnen Pflanzenart dienten, in direktem oder indirektem Kontakt mit dem beimpften Erdsubstrat, der Simulation der Edaphosphärebedingungen grüner Pflanzen für das Pilzmyzel. Abgesehen von einigen Leguminosen mit hochgradig stimulierendem Rhizosphäreneffekt erwiesen sich alle Rasenarten nach dem Aufsetzen auf das Erdsubstrat vor allem als Hindernis für den Abtransport der flüchtigen Hemmstoffe, die in dem Erdsubstrat selbst produziert werden. Die Myzelentwicklung wurde, mit einigen Ausnahmen, weder von nicht flüchtigen noch von gasförmigen Ausscheidungen der Wurzelballen stimuliert. Es wird gefolgert, daß die Myzelentwicklung im Erdsubstrat der Edaphosphäre sowohl durch die eingeschränkte Abgabe von gasförmigen Metaboliten aus der Erde selbst wie auch von Exhalationen der lebenden Pflanzenpopulation und der verrottenden Pflanzenteile gehemmt ist. Als besonders effektiv erscheinen CO2 und Substanzen aus verrottendem pflanzlichen Material. Des weiteren erwies sich der Hexenringpilz Lepista nuda als fakultativ nekrotropher Parasit gegenüber klimatisch geschwächten grünen Pflanzen bei einer geringen Ausnutzung der Unterrasenerde. Im Gegensatz dazu verwerteten Agaricus porphyrizon und Agrocybe praecox in erster Linie das Erdsubstrat mit einer gewissen Einbeziehung von pflanzlichen Resten. Ihre scheinbare Bindung an grüne Pflanzen beruht auf der Förderung der Fruchtbildung, nicht aber des Myzelwachstums, im pflanzlichen Ökosystem.

Nutritional studies on species and mutants of Lepista, Cantharellus, Pleurotus and Volvariella.

The purpose of this study is to determine the ability of select Agaricales species to utilize various sources of carbon, nitrogen, vitamins, and growth hormones. Fungi selected for the studies include:Cantharellus clavatusFries,C. cibariusFries,Lepista nuda (Bull. ex. Fries)Cooke,Pleurotus ostreatus (Jacq. ex. Fries)Kummer, andVolvariella volvacea (Bull. ex. Fries)Singer. Three strains ofC. cibarius and one mutant ofV. volvacea (V135), V134, were employed to determine if nutritional requirement differences occurred. One species,V. volvacea, is grown commercially as a cottage industry in the Orient (Alicbusan &Ela, 1961) while the other species currently have no commercial value. All species studied possess pleasing flavors and have potential use in the mushroom production industry.

Surface Replicas of the Spores of Fleshy Fungi

SUMMARYSingle- or two-stage surface replicas were made of the following: Clitopilus prunulus, Leucopaxillus albissimus var. lentus, Laccaria laccata, Laccaria trullisata, Clitocybe asterospora, Clitocybe inversa, Clitocybe highlandensis, Lepista caespitosa, Lepista sordida, Lepista irina var., Lepista nuda, Lepista sp., Russula dissimulans, Lactarius sp., Cantharellus floccosus.Various means of preparation and comments upon their utility are reported along with the electron micrographs. Some of the results contribute information which is of direct application to taxonomy while others only illustrate the variation of spore ornamentation and the resolution of surface structure.