DNA marking of some quantitative trait loci in the cultivated edible mushroom <Emphasis Type="Italic">Pleurotus ostreatus</Emphasis> (Fr.) Kumm.

Fungi of the genus Pleurotus, in particular, species Pleurotus ostreatus (common oyster mushroom) are among most cultivated fungi in the world. Due to intense rates of development of studies in this field, efficient breeding programs are highly required in the search for new P. ostreatus strains. The principal traits used worldwide for selecting strains are intensity of fruitbearing, fruit body cap color (for some consumptive markets), and mycelium growth rate. In this connection, the objective of this work was to study these quantitative traits and to find molecular markers, which could be employed to accomplish breeding programs. In general, we found 12 genomic loci (quantitative trait loci, QTLs) controlling mycelium growth rate of oyster and six QTLs responsible for the fruit body cap color. The genetic map of P. ostreatus was constructed, and all markers of quantitative traits found by us were located on this genetic map. The obtained linkage map can be a useful tool for the accomplishment of breeding programs to improve economically important traits of oyster mushroom.     

Use of molecular markers for differentiation of cultivated strains of oyster and button mushrooms

Analysis of commercial strains of two edible mushrooms, Pleurotus ostreatus and Agaricus bisporus, using PCR and isozyme electrophoresis techniques allowed us to differentiate groups of genetically similar and distant strains. Among the commercial strains of P. ostreatus, the level of genetic variation was higher suggesting a broader genetic basis employed in breeding of this mushroom. The cultivars and hybrids of, A. bisporus, showed a higher level of homology. The isozyme markers (nonspecific esterase, leucinaminopeptidase, and phosphoglucoisomerase) are recommended for identification of the commercial strains of edible mushrooms.     

Synergistic activation of the rat laminin gamma1 chain promoter by the gut-enriched Kruppel-like factor (GKLF/KLF4) and Sp1

Laminin is a multifunctional heterotrimeric protein present in extracellular matrix where it regulates processes that compose tissue architecture including cell differentiation. Laminin γ1 is the most widely expressed laminin chain and its absence causes early lethality in mouse embryos. Laminin γ1 chain gene (LAMC1) promoter contains several GC/GT-rich motifs including the bcn-1 element. Using the bcn-1 element as a bait in the yeast one-hybrid screen, we cloned the gut-enriched Kruppel-like factor (GKLF or KLF4) from a rat mesangial cell library. We show that GKLF binds bcn-1, but this binding is not required for the GKLF-mediated activation of the LAMC1 promoter. The activity of GKLF is dependent on a synergism with another Kruppel-like factor, Sp1. The LAMC1 promoter appears to have multiple GKLF- and Sp1-responsive elements which may account for the synergistic activation. We provide evidence that the synergistic action of GKLF and Sp1 is dependent on the promoter context and the integrity of GKLF activation and DNA-binding domain. GKLF is thought to participate in the switch from cell proliferation to differentiation. Thus, the Sp1–GKLF synergistic activation of the LAMC1 promoter may be one of the avenues for expression of laminin γ1 chain when laminin is needed to regulate cell differentiation.     

The Biosynthesis of Low-Molecular-Weight Nitrogen-Containing Secondary Metabolites—Alkaloids—by the Resident Strains of Penicillium chrysogenum and Penicillium expansum Isolated on Board the Mir Space Station

The analysis of the absorption spectra of the low-molecular-weight nitrogen-containing secondary metabolites—alkaloids—of four Penicillium chrysogenum strains and six P. expansum strains isolated on board the Mir space station showed that all these strains synthesize metabolites of alkaloid origin (roquefortine, 3,12-dihydroroquefortine, meleagrin, viridicatin, viridicatol, isorugulosuvin, rugulosuvin B, N acetyltryptamine, and a yellow metabolite containing the benzoquinone chromophore).     

Interspecific genetic variability of the oyster mushroom Pleurotus ostreatus as revealed by allozyme gene analysis

Allozyme variation in natural populations of basidiomycetes fungus Pleurotus ostreatus (88 individuals) from three regions of central Russia was studied. The species was shown to have 92.86% of polymorphic allozyme loci and expected heterozygosity He = 0.49. The mean number of alleles per locus was 3.5. The genetic differences among populations were supported by F-statistics (FST = 0.750). The low level of inbreeding (FIS = 0.018) suggests that the P. ostreatus populations are panmictic, and the main reproduction mode involves basidiospores dispersing at long distances. Using cluster analysis, geographically isolated populations and intersterile groups were differentiated within the complex P. ostreatus species.     

Differentiation of closely related oyster fungi Pleurotus pulmonarius and P. ostreatus by mating and molecular markers

Matings and RAPD-PCR analysis were used to differentiate two closely related basidiomycetes fungi, Pleurotus pulmonarius and P. ostreatus, which are widespread in Russian forest biocenoses with moderate continental climate. Monokaryon-monokaryon (mon-mon) and dikaryon-monokaryon (di-mon) matings demonstrated complete reproductive isolation of the two species, which have partly overlapping morphological traits. The prevalence of a particular species in nature was shown to depend to a great extent on the natural conditions, namely, the day and night temperature fluctuations. The clustering of natural Pleurotus strains displayed two trends: one was associated with natural reproductive isolation of the two species (D = 0.61) and the other, with the geographical factor (D = 0.39). A relatively recent origin is suggested for the divergence of the two species and the reproductive barrier between them. Adaptation to natural conditions was considered to be the main factor causing the divergence of natural Pleurotus populations and, eventually, allopatric speciation.     

Molecular Polymorphism of β-Galactosidase LAC4 Genes in Dairy and Natural Strains of Kluyveromyces Yeasts

Molecular Biology - The ability to ferment lactose is a characteristic peculiarity of dairy Kluyveromyces lactis yeasts; the vast majority of other yeast species are not able to assimilate this...     

Interspecific Genetic Variability of the Oyster Mushroom Pleurotus ostreatusAs Revealed by Allozyme Gene Analysis

Allozyme variation in natural populations of basidiomycete fungus Pleurotus ostreatus (88 individuals) from three regions of central Russia was studied. The species was shown to have 92.86% of polymorphic allozyme loci and expected heterozygosity H _e = 0.49. The mean number of alleles per locus was 3.5. The genetic differences among populations were supported by F-statistics (F _ST = 0.750). The low level of inbreeding (F _IS = 0.018) suggests that the P. ostreatus populations are panmictic, and the main reproduction mode involves basidiospores dispersing at long distances. Using cluster analysis, geographically isolated populations and intersterile groups were differentiated within the complex P. ostreatus species.