| With the development of edible fungi industry,obtaining more excellent strains has also become a research hotspot.The breeding of Pleurotus mainly adopts hybridization,and obtaining parental monokaryon is the basis and guarantee of the whole breeding work.Different mating types of mononucleoids can undergo affinity reactions to form lock like associations,which can be used to identify different mating types of mononucleoids,improve the success rate of hybrid breeding,and obtain more hybrid offspring.Therefore,further clarifying the mating type system of Pleurotus and identifying the mating types of different parents is of great significance for Pleurotus breeding work.In this study,eight different Pleurotus strains preserved in the laboratory were screened according to agronomic characters and biological transformation rate.After obtaining the target strain,conduct systematic research on mating type,and use genome sequencing technology to identify and analyze mating type genes;The main results of affinity analysis and hybrid breeding research on strains that obtained monokaryotic mating types are as follows:(1)A comparative analysis was conducted on the 8 strains of Pleurotus preserved in the laboratory based on various aspects such as mycelial growth rate,primordial time,fruiting body morphological characteristics,and biological transformation rate.The results showed that Pinggu had better mycelial growth potential,good fruiting body leaf thickness and toughness,and higher biological transformation rate compared to the wild variety DY70.(2)The microscopic observation of the screened strains of Pinggu and DY70 showed that they were typical Pleurotus,and the mycelium contained interlocking associations;The shape of the basidium is like a stick,with 4 basidiophores on each basidium,and the front end of the small stem contains basidiospores;The spores are printed in white and have a cylindrical shape.The ITS identification and phylogenetic tree of the wild species DY70 showed that belonged to Pleurotus florida.(3)Accurate identification of mating types of selected strains of Pinggu and DY70 was carried out using methods of protoplast mononucleosis and spore mononucleosis.The results showed that the protoplast mononucleosis rates of Pinggu and DY70 strains were both low;Through routine mating experiments,it was determined that both strain Pinggu and strain DY70 were fourth grade heterothallic basidiomycetes,and their mating type was A1A2B1B2.X~2 test showed that the separation of spore monokaryons followed Mendelian genetic laws.Comparing the mycelial growth rate of different mating types of unikaryons,it was found that the relationship between the four polar mycelial growth rates in Pinggu was A1B2>A2B1>A1B1>A2B2;In DY70,the growth rate of four polar hyphae is A1B1>A1B2>A2B1>A2B2.(4)Fungal framework analysis was conducted on the two compatible and unikaryotic B3and B8 of Pinggu,and the obtained genomic data was used for homologous alignment to identify mating type genes.The results showed that the HD genes of B3 were HD1-1,HD1-2,and HD2-1,while B8 contained HD1-1,HD1-2,HD1-3,and HD2-1,with HD1arranged in a"head to head"manner,adjacent to HD2 and MIP genes.A pheromone receptor gene and a matching pheromone precursor gene were found in B3 and B8.(5)Using the monocytes of Pinggu and DY70 as materials,the affinity between Pinggu and DY70 was analyzed using a single mating method.It was found that there was an compatible mating reaction between Pinggu and DY70,and both had the same mating type and contained the same A1A2B1B2.A total of 12 hybrid strains with genetic differences were screened through antagonistic experiments on compatible mycelium and parents.Through measurement and comparison of mycelial growth rate,it was found that the mycelial growth rate of Z4 and Z7 hybrid strains was better than that of their parents. |
