Abstract: In order to breed new strains combining the elite complementary traits of Pleurotus ostreatus and Pleurotus eryngii, Pleurotus ostreatus variety CCEF89 with the properties of high yield and strong ability to resist contamination, and Pleurotus eryngii variety PL7 with the properties of high quality and strong adaptability were used as the parent strains to build the PEG (polyethylene glycol)protoplast fusion system.Under the optimal protoplast fusion condition of 1∶1 quantity ratio of the parent strains, 32 ℃ water bath, 30% PEG 6000, 0.01 mol·L^-1 Ca²⁺ and 30 min co-incubation, the fusion rate was up to 0.010 1%-0.028 2%. 12 protoplast fusants (P1-P12) were identified by antagonistic reaction test and Rep-PCR molecular identification from 515 protoplast fusion regeneration isolates. After the mushroom cultivation experiments, P1 and P5 were identified as new strains of P. eryngii, and the other 10 protoplast fusants were new strains of P. ostreatus. The mushroom yield and biological efficiency of new strains P1 and P5 were significantly higher than those of their parent PL7, and their ability to resist contamination were increased significantly. Comparing to the parent CCEF89, the time of medium cultivation and mushroom primordia formation of P. ostreatus new strains P4, P10 and P11 were 5.5-7.3 days earlier, the yield of the first harvest mushroom and the total biological efficiency increased by 18.0%-24.0% and 21.00%-27.67%, respectively.Using the protoplast fusion technology, we acquired P. ostreatus and P. eryngii new strains with excellent complementary properties of the parents simultaneously, and proposed a new pathway to innovate new germplasm resources and bred new varieties of two different edible fungiat the same time.

Key words: protoplast fusion, Pleurotus ostreatus, Pleurotus eryngii, fusant, germplasm resource