Examining genetic relationships of Chinese Pleurotus ostreatus cultivars by combined RAPD and SRAP markers

Assessment of Genetic Diversity among Pleurotus spp. Isolates from Jordan

Pleurotus is considered an important genus that belongs to the family Pleurotaceae and includes the edible King Oyster mushroom (Pleurotus eryngii). In the present study, 19 Pleurotus isolates were collected from two locations in the north of Jordan (Tell ar-Rumman and Um-Qais). The morphological characteristics among collected isolates revealed that there was a morphological similarity among the collected isolates. Nucleotide sequence analysis of the internal transcribed spacer (ITS1⁻5.8S rDNA⁻ITS4 region) and 28S nuclear large subunit (nLSU) in the ribosomal DNA gene of the isolated stains showed that all of them share over 98% sequence similarity with P. eryngii. Genetic diversity among the collected strains was assessed using inter simple sequence repeat (ISSR) analysis using 18 different primer pairs. Using this approach, 141 out of 196 bands obtained were considered polymorphic and the highest percentage of polymorphism was observed using primer UBC827 (92.3%) with an overall Polymorphism Information Content (PIC) value of 70.56%. Cluster analysis showed that the Jordanian Pleurotus isolates fall into two main clades with a coefficient of similarity values ranging from 0.59 to 0.74 with a clear clustering based on collection sites. The results of the present study reveal that molecular techniques of ISSR and rDNA sequencing can greatly aid in classification and identification of Pleurotus spp. in Jordan.

Development of SCAR markers to determine the mating types of Lepista nuda protoplast monokaryons

Lepista nuda (Bull. ex Fr.) Cooke belongs to Tricholomataceae and is an edible fungus with both economic and medical value. Mycelia were isolated from the fruiting bodies of L. nuda and were used to prepare the protoplast monokaryons. One hundred and fifteen monokaryons were obtained and their mating types were determined using somatic incompatibility tests. Protoplast monokaryons segregated into either the A1B1 or the A2B2 mating types. Inter-simple sequence repeats and sequence-related amplified polymorphism fingerprinting were used to analyse the mating types of these protoplast monokaryons and 16 sequence-characterised amplified region primers were developed to efficiently differentiate between the monokaryon mating types. Multiplex PCR analyses were also established. The data presented here outline a method for the precise and rapid identification of protoplast monokaryon mating types, which has the promise to shorten the period required for conventional crossbreeding.

Genetic diversity of Pleurotus pulmonarius revealed by RAPD, ISSR, and SRAP fingerprinting

Pleurotus pulmonarius is one of the most widely cultivated and popular edible fungi in the genus Pleurotus. Three molecular markers were used to analyze the genetic diversity of 15 Chinese P. pulmonarius cultivars. In total, 21 random amplified polymorphic DNA (RAPD), 20 inter-simple sequence repeat (ISSR), and 20 sequence-related amplified polymorphism (SRAP) primers or primer pairs were selected for generating data based on their clear banding profiles produced. With the use of these RAPD, ISSR, and SRAP primers or primer pairs, a total of 361 RAPD, 283 ISSR, and 131 SRAP fragments were detected, of which 287 (79.5 %) RAPD, 211 (74.6 %) ISSR, and 98 (74.8 %) SRAP fragments were polymorphic. Unweighted Pair-Group Method with Arithmetic Mean (UPGMA) trees of these three methods were structured similarly, grouping the 15 tested strains into four clades. Subsequently, visual DNA fingerprinting and cluster analysis were performed to evaluate the resolving power of the combined RAPD, ISSR, and SRAP markers in the differentiation among these strains. The results of this study demonstrated that each method above could efficiently differentiate P. pulmonarius cultivars and could thus be considered an efficient tool for surveying genetic diversity of P. pulmonarius.