Genetic and Chemical Diversity of Edible Mushroom Pleurotus Species

The genus Pleurotus is one of the most widely cultivated and edible mushrooms with various cultivators. Three molecular characteristics were used to evaluate the genetic diversity of 132 tested samples. Phylogenetic analysis showed five clades for tested samples of the genus Pleurotus by the combined ITS and LSU sequences with strong bootstraps and Bayesian posterior probability supports. A total of 94 polymorphic fragments ranging from 10 to 100 bp were observed by using an intersimple sequence repeat (ISSR) marker. The DNA fragment pattern showed that P. ostreatus cultivator (strain P9) was clearly distinguished from wild strain based on their clear banding profiles produced. DNA GC content of the genus Pleurotus varied from 55.6 mol% to 43.3 mol%. Their chemical composition was also determined, including sugar, amino acid, polar lipid, mycolic acid, quinone, and fatty acid, which presented some high homogeneity. Most of the tested samples contained mycolic acid; glucose and arabinose as the main sugars; aspartic acid, arginine, lysine, tyrosine, and alanine as the main amino acids; and C16:0, C18:0, C18:2cis-9,12, anteiso-C14:0, and summed feature 8 as the main fatty acids. In addition, their polar lipid profiles were investigated for the first time, which significantly varied among Pleurotus species. The genus Pleurotus contained menaquinone-6 as the sole respiratory quinone, which showed a significant difference with that of its closely related genera. These results of this study demonstrated that the combined method above could efficiently differentiate each Pleurotus species and thus be considered an efficient tool for surveying the genetic diversity of the genus Pleurotus.

AMINO ACID COMPOSITION AND ANTI-TYROSINASE ACTIVITY OF METABOLITES FROM EDIBLE Pleurotus SPECIES FOR THEIR NUTRITIONAL AND THERAPEUTIC POTENTIAL

Mushrooms are being extensively researched due to their nutritional value and medicinal importance. The genus Pleurotus is the second most cultivated mushroom and is known for its high nutritional value, therapeutic properties, taste, flavor, as well as their application in biotechnology and environmental study. Also, tyrosinase is prevalent in most living organisms. The enzyme catalyzes the oxidation of monophenols to ortho-quinones in a two-step reaction process. This study was aimed to assess the amino acid composition and anti-tyrosinase activity of metabolites obtained from edible Pleurotus species. Assessment of the nutritional content and inhibitory studies of mushroom tyrosinase produced from four Pleurotus strains was carried out using high-performance liquid chromatography (RP-HPLC). The results of the study showed that seventeen different amino acids were identified in the crude and partially purified protein metabolites. Also, the crude extract metabolite had the highest quantity of amino acids than the partially purified. The highest and lowest amino acids value Glutamic acid (1343.26 µmol/mL) and valine (0.34 µmol/mL). The anti-tyrosinase inhibition studies of the four Pleurotus strains showed varying results from significantly inhibitory effects to slightly inhibitory effects on mushroom tyrosinase. The highest inhibition was 14.86% (Pleu-W), while the lowest inhibition was 51.42% (Plof-30) respectively. The high point of this study is that the Pleurotus species contains a significant number of amino acids and also, they possess good anti-tyrosinase activity. Therefore, these are a good source of nutritional and therapeutic metabolites and these can be explored further for their nutritional and medicinal importance to man.

Volatile Profiling of Pleurotus eryngii and Pleurotus ostreatus Cultivated on Agricultural and Agro-Industrial By-Products

The influence of genetic (species, strain) and environmental (substrate) factors on the volatile profiles of eight strains of Pleurotus eryngii and P. ostreatus mushrooms cultivated on wheat straw or substrates enriched with winery or olive oil by products was investigated by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Selected samples were additionally roasted. More than 50 compounds were determined in fresh mushroom samples, with P. ostreatus presenting higher concentrations but a lower number of volatile compounds compared to P. eryngii. Roasting resulted in partial elimination of volatiles and the formation of pyrazines, Strecker aldehydes and sulfur compounds. Principal component analysis on the data obtained succeeded to discriminate among raw and cooked mushrooms as well as among Pleurotus species and strains, but not among different cultivation substrates. Ketones, alcohols and toluene were mainly responsible for discriminating among P. ostreatus strains while aldehydes and fatty acid methyl esters contributed more at separating P. eryngii strains.

Differentiation of Two Pleurotus Species Based on the Restrictive Digestion Profile of the Internal Transcribed Spacer Region

Two oyster mushrooms (Pleurotus eous P-31 and P. ostreatus EM-1) are under either cottage industry or semi-commercial cultivation in Ghana. The latter (P. ostreatus) is already well known to the public and on the shelf of some leading supermarkets. There is morphological resemblance between the two species making it difficult for the untrained eye to distinguish between them except for the colour difference. In this study, molecular methods were em­ployed to differentiate among the two species. The Internal Transcribed Spacer ITS 1 and ITS 4 regions of the rDNA of the two oyster species were amplified by the conventional PCR using the universal primer pair, ITS 1 and ITS 4 followed by restrictive digestion with enzymes, (Hh I, Hinf I, Rsa I and Hae III). The two species could not be separated based on the ampli­fied bands only, as both produced a characteristic band size of 650 bp. Gel profiling showing restrictive patterns generated by the four enzymes indicated that only the Hae III restrictive enzyme was effective in separating P. eous P-31 and P. ostreatus EM-1. This is the first record of the separation of the Ghanaian Pleurotus species by molecular methods indicating their genetic differences.

Characterizing Fungal Decay of Beech Wood: Potential for Biotechnological Applications

The biotechnological potential of nine decay fungi collected from stored beech logs at a pulp and paper factory yard in Northern Iran was investigated. Beech blocks exposed to the fungi in a laboratory decay test were used to study changes in cell wall chemistry using both wet chemistry and spectroscopic methods. Pleurotus ostreatus, P. pulmonarius, and Lentinus sajor-caju caused greater lignin breakdown compared to other white-rot fungi, which led to a 28% reduction in refining energy. Trametesversicolor caused the greatest glucan loss, while P. ostreatus and L. sajor-caju were associated with the lowest losses of this sugar. Fourier transform infrared spectroscopy (FTIR) analyses indicated that white-rot fungi caused greater lignin degradation in the cell walls via the oxidation aromatic rings, confirming the chemical analysis. The rate of cellulose and lignin degradation by the T.versicolor and Pleurotus species was high compared to the other decay fungi analyzed in this study. Based on the above information, we propose that, among the fungi tested, P. ostreatus (27.42% lignin loss and 1.58% cellulose loss) and L. sajor-caju (29.92% lignin loss and 5.95% cellulose loss) have the greatest potential for biopulping.

Phytochemical Characteristics Evaluation of Pleurotus species Cultivated on Agricultural Wastes in Chiro, Ethiopia

Background: Mushrooms are a nutritious food source, being rich in protein, vitamins and minerals. They are also contains substances that enhance the immune system, fight infectious disease. Mushrooms can be cultivated on a variety of substrates, including agricultural and agro-industrial waste materials. The current study was amid to evaluate the phytochemical characteristics of Pleurotus species cultivated on different agricultural wastes.Methods: Mushrooms Pleurotus ostreatus and Pleurotus florida were cultivated on different agricultural wastes for the screening of phytochemical characteristics. Qualitative analyses of the phytochemicals were evaluated in methanolic, ethanolic and aqueous extracts of both Pleurotus spp. Total phenolic and total flavonoid contents of the extracts were determined by using Folin-Ciocalteu method and Spectrophotometric method with aluminum chloride.Result: Qualitative analyses revealed the phytochemicals alkaloids, saponins, flavonoids and tannins were present in methanolic, ethanolic and aqueous extracts of both Pleurotus spp. while anthraquinones and Phlobatannins were absent in aqueous extracts. The highest concentration of phenols and flavonoids were recorded in methanolic extracts of P. ostreatus and P. florida (48.17 mg GAE/g of extract and 56.57 mg of RUE/g of extract and 46.73 mg GAE/g of extract and 55.58 mg of RUE/g of extract respectively). The results supported the methanolic extracts of P. ostreatus and P. florida might indeed be potential sources of phytochemicals.

Genomic analyses of two Italian oyster mushroom Pleurotus pulmonarius strains

Pleurotus mushrooms are among the most cultivated fungi in the world and are highly valuable for food, medicine, and biotechnology industries. Furthermore, Pleurotus species are carnivorous fungi; they can rapidly paralyze and kill nematodes when nutrient-deprived. The predator–prey interactions between Pleurotus and nematodes are still widely unexplored. Moreover, the molecular mechanisms and the genes involved in the carnivorous behavior of Pleurotus mushrooms remain a mystery. We are attempting to understand the interactions between Pleurotus mushrooms and their nematode prey through genetic and genomic analyses. Two single spores (ss2 and ss5) isolated from a fruiting body of Pleurotus pulmonarius exhibited significant differences in growth and toxicity against nematodes. Thus, using PacBio long reads, we assembled and annotated two high-quality genomes for these two isolates of P. pulmonarius. Each of these assemblies contains 23 scaffolds, including 6 (ss2) and 8 (ss5) telomere-to-telomere scaffolds, and they are among the most complete assembled genomes of the Pleurotus species. Comparative analyses identified the genomic differences between the two P. pulmonarius strains. In sum, this work provides a genomic resource that will be invaluable for better understanding the Italian oyster mushroom P. pulmonarius.