Quality evaluation and genetic relation identification for different Poria cocos strains

ObjectiveQualities of different Poria cocos strains were evaluated in the study and their genetic relations were identified to provide reference for the rational utilization of P.cocos and breeding of fine strains.MethodEleven P.cocos strains from various sources were research objects.Their mycelial growth rates were detected through planar cul-ture,sclerotium yields were determinated through cultivation using pine tree pocket,genetic stabilities were identified through repeated switching method.The genomes were extracted from these strains,ITS sequence were amplified by PCR and then ITS sequences were analyzed,and phylogenetic tree was established.Meanwhile,hypha antagonism among the strains was detected,and the genetic relations of P.cocos strains were further investigated combining ITS sequence re-sults.ResultAmong the 11 tested strains,mycelial growth rate,sclerotium yield and genetic stability of strains No.8,No.9 and No.12 were better than others,but those of strains No.1,No.7 and No.13 ranked the bottom.ITS sequence length of P.cocos was 1600 bp.According to the sequence analysis,homology of strains No.1,No.2,No.3,No.4,No.7 and No.10 was 100% with Wolfporia cocos intemaltranscribed spacer1,and the homology of strains No.8,No.9,No.11,No.12 and No.13 was 99% with Wolfporia cocos strain LP-13.These results indicated that the tested strains belonged to two subspecies.Phylogenetic tree indicated that,strains No.1,No.2,No.3,No.4,No.7 and No.10 clustered into one group,and their genetic relations were close,which meant these strains might be the same species with different names.Strains No.8,No.9,No.11,No.12 and No.13 clustered into a group with large genetic relations among them,which indi-cated that there might be difference within the species.ConclusionEvaluating the quality of P.cocos via determinating mycelial growth rate,sclerotium yield and hereditary stability is viable.ITS sequence analysis can identify the strains to species level,and explicit the genetic relationship between strains.