Identification and physiological properties of a Nigerian strain of Volvariella sp. isolated from oil palm waste.

Over the years several species of edible mushrooms have been collected for consumption from different agro-wastes in Nigeria. Identification of most of these mushrooms was often by morphological descriptive methods. This study reports the morphological study, physiological study and identification of a Nigerian wild strain of Volvariella sp. (VNW) isolated from discarded oil palm waste and three Indian commercial strains V11, V245 and V247 of V. volvacea. Effect of incubation temperatures and medium pH was investigated. Molecular characterization of the strains was carried out using ITS-1 and ITS-4 primers. Results obtained showed close similarities of the Nigerian strain to the Indian strains with few morphological variations in colour, shape and appearance. Growth was observed at temperature range of 20-40 °C and pH range of 4.0-8.0 for all strains with optimum mycelia extension at 35 °C and pH 6.0. VNW recorded a significantly higher (p ≤ 0.05) mycelia extension rate at 35 °C (25.20 ± 1.80 mm/day) and pH 6.0 (40.20 ± 0.34 mm/day). Highest biomass yield was observed at pH 6.0 with V11 recording a significantly (p ≤ 0.05) higher yield (1.74 ± 0.07 g/100 mL). Increasing percentage (w/v) of CaSO4·H2O increased biomass yield of all the strains. NJ phylogenetic tree showed the Nigerian and Indian strains in the same cluster indicating evolutionary closeness than with other species of Volvariella from GenBank in a separate cluster even though they share a common ancestor. This successfully proves the identity of a Nigerian strain of Volvariella sp. VNW from oil palm waste as V. volvacea with GenBank accession number KC894923.

Screening of biological, morphological, and molecular characteristics of single-spore isolate collections of the straw mushroom, Volvariella volvacea (higher Basidiomycetes) from India.

Of the 2 parent strains and 6 single-spore isolates (SSIs) used in this study, the SSIs BBSR-007 and BBSR-002 of the culinary-medicinal straw mushroom Volvariella volvacea exhibited superior growth characteristics on different growth media. These also took less time until first harvest (days after spawning), gave higher numbers of fruiting bodies per unit weight of substrate, and provided a higher mushroom yield on composted substrate. The fruiting body weight of isolate BBSR-007 was significantly higher compared to BBSR-002. On pasteurized paddy straw, the SSI BBSR-007 had a higher mushroom yield than BBSR-002. The contents of dry matter, protein, and other elements (sodium, potassium, and calcium) were on par in both the parent strains and different SSIs, except SSI OE-55-08, which had highest dry matter, protein content, and potassium/-to-odium ratio. In amplified ribosomal DNA restriction analysis, the SSIs did not show any distinctness, whereas in amplified fragment length polymorphism, the SSI OE-55-08 of parent strain OE-55 formed a separate clade; of 4 SSIs of strain OE-274, the SSI BBSR-003 formed a separate clade than other SSIs. The genetically distinct SSI OE-55-08 produced the highest numbers of fruit bodies per unit weight of substrate and exhibited the highest amounts of dry matter and protein in its fruit bodies. Another slightly distinct SSI, BBSR-003, formed white aerial mycelia on growth substrate, and its fruit bodies exhibited the highest levels of sodium and calcium.

Death by edible mushroom: first report of Volvariella volvacea as an etiologic agent of invasive disease in a patient following double umbilical cord blood transplantation.

We describe a case of invasive fungal infection caused by Volvariella volvacea following double umbilical cord blood transplantation (UCBT). Although infections caused by several mushroom species have been documented, we believe this to be the first published report of invasive infection with Volvariella volvacea, an edible mushroom belonging to Agaricales.