[Use of ITS and ISSR markers in the molecular characterisation of Pleurotus djamor hybrid strains]

Identification techniques and detection methods of edible fungi species

Edible fungi have high nutritional value and great potential. Confusion among edible fungi species, and foodborne diseases due to toadstool poisoning or death induced by inadvertent consumption exist across the world. Therefore, edible fungi must be accurately identified. Based on different substances in edible fungi, there are different detection methods, and the same method can use different identification technology. Sensory identification methods include morphological and odor methods. Instrumental analysis methods based on chemical composition include chromatographic, mass spectrometry and spectral technology. Molecular biology identification methods based on nucleic acids include molecular marker technology, sequencing technology, isothermal amplification technology and endogenous reference gene method. Method is channel, and technology is the means. The principles, advantages, disadvantages and applications of various identification techniques and detection methods were discussed in this work to provide reference for the identification research of edible fungi and technical support for preventing food safety incidents caused by toadstools.

Data-Mining Techniques: A New Approach to Identifying the Links among Hybrid Strains of Pleurotus with Culture Media

In this study, a data set of mycelial and cultural characteristics of hybrid strains of Pleurotus ostreatus and Pleurotus djamor were analyzed using three data-mining techniques: the K-medoids clustering algorithm, PCA biplot and the association rules algorithm. The characteristics evaluated were as follows: maximum velocity; lag phase; biomass; and exopolysaccharides content in the cultivation of 50 hybrid strains of Pleurotus ostreatus and 50 hybrid strains of Pleurotus djamor. Different mixtures of culture media were used to supplement Ecuadorian agricultural products. Data of the parameters obtained in the experimental methods were grouped into four clusters, obtaining a presentation of the hybrid strains of Pleurotus with a higher relation to each characteristic measured. Data-mining tools showed the hybrid strains cultivated on solid-culture media (M1 = malt extract agar and rice flour) and liquid-culture media (L1 = maltose, yeast extract and rice flour) presented the highest mycelial and cultural characteristics. These results are good indicators to improve the industrial production of edible fungi by using rice flour in the cultivation, contributing to the mushroom market and circular economy.

Characterization of Pleurotus djamor neohaplonts recovered by production of protoplasts and chemical dedikaryotization

Production of hybrid strains is accomplished by mating monosporic isolates or neohaplonts, obtained either by chemical dedikaryotization or by production of protoplast. However, differences in growth rate among recovered neohaplonts have been reported. The presence of phenotypic and genetic changes among the neohaplonts recovered either by chemical dedikaryotization or by production of protoplast, was evaluated by measuring growth and morphology, and by molecular characterization using six ISSR markers to identify polymorphisms. Neohaplonts recovered by both methods presented variation in growth rate depending on their compatibility type and recovery method. Using ISSR markers, 59.2% polymorphism was established. Neohaplonts recovered by both monokaryotization procedures presented differences in growth rate and polymorphism.

Pleurotus opuntiae revisited - An insight to the phylogeny of dimitic Pleurotus species with emphasis on the P. djamor complex

The name Pleurotus opuntiae is indiscriminately used for describing mushrooms with white to off-white to white-grey pilei with short or absent stipe and dimitic hyphal system, which grow on plants of the genera Opuntia, Yucca, Agave, Phytolacca etc. However, the outcome of the present study evidences that this name should be reserved for specimens deriving from the Mediterranean area only; an epitype originating from Italy on Opuntia ficus-indica is designated. Pertinent material was sequenced by using the internal transcribed spacer region (ITS) and found to be phylogenetically related to P. djamor from Kenya and Nigeria, while members of the P. djamor complex from other continents were clearly more distant. Results were further corroborated by examining the large subunit of nuclear ribosomal DNA (LSU) and the second subunit of RNA polymerase II (RPB2). The P. djamor complex shows high intraspecific polymorphism evidenced by sequence divergence and genetic distance values, presents a cosmopolitan distribution and also comprises material initially identified as P. flabellatus, P. opuntiae, P. ostreatoroseus, P. parsonsiae and P. salmoneostramineus. An ITS tree including representative specimens from all major Pleurotus species is provided for the first time and ambiguous taxa are discussed in the context of new findings.