Evaluation Of Germplasm Resources Of Morchella And Microbial Diversity Of Representative Strains During Its Cultivation

Morchella is a rare edible and medicinal mushroom with high nutritional value and unique fragrance,and which is globally distributed,and favored by domestic and foreign consumers.Eighteen strains of Morchella from Yunnan and Guangxi of China were evaluated,their biological characteristics,genetic diversity,cultivation in field and soil microbial diversity of strain M18 were comparative study.This research will provides the theory basis for the morels industrialized cultivation and provide material for the breeding of high-yielding varieties of morels.The main results are as follows:1.Biological characteristics of 8 strains of wild morelsThe optimum mycelium growth temperature and p H of 8 strains of wild morels were 20-25℃and 6.5-8.0 respectively.Among the tested strains,soluble starch was the optimal carbon source for five strains,including M1,M2,M4,M5 and M6,strain M5 showed the greatest mycelium growth rate(0.88 cm/d).Sucrose was the best carbon source for strain M1,M2 and M3,while the optimal carbon sources of strain M7 and M16 were glucose and maltose,respectively.The optimum nitrogen sources of strains M1-M5 and M16 were wheat bran and peptone.Peptone was the optimal nitrogen source for M6 and M7.Most strains grew best when the carbon-nitrogen ratio was 10/1-30/1,and the optimum carbon-nitrogen ratio was 10/1.2.Genetic diversity of the tested strainsAntagonistic test showed that the 18 strains of Morels could be divided into2 groups,one with strains M1-M15,M17 and M18,and the other with M16.By combined analysis of multiple genes,wild strains of M1,M2,M3 and M4 were identified as Morchella septimeleta,M5,M6 and M7 as Morchella sextelata,and strain M16 as Morchella crassipes.Phylogenetic analyses on the multiple genes of eighteen strains of morels identified two major clades,the black morel branch(M1-M15,M17,M18)and the yellow branch(M16).Among of the black morel strains Morchella septimeleta,Morchella sextelata,and Morchella importuna were identified,while the yellow morel with only one species Morchella crassipes.Twelve proper with rich polymorphism were selected from100 ISSR primers,with these 12 primers,a total of 145 bands were amplified from 18 strains of Morchella,among which 134 bands were polymorphism bands,with a polymorphism rate of 92.41%,eighteen strains of Morchella could be divided into four Clusters at similarity coefficient of 0.62 by UPGMA cluster analysis,ClusterⅠincludes M1,M2,M3 and M8,ClusterⅡincludes M12,M13 and M14;ClusterⅢincludes M5,M6 and M7,M9,M10,M11,M17 and M18,M16 in ClusterⅣ.3.Artificial cultivation test of the tested strainThe results of field cultivation showed that the main cultivated strain M18had the best comprehensive performance,with a production cycle of 138 days,a primordia density of 1.24/cm~2,a fruiting density of 136.67/m~2,a fresh fruiting yield of 1247.56 g/m~2 and a dry-wet ratio of 14.79%.Among the wild strains,M2 and M4 showed the greatest development potential,with the production cycle of 115 and 116 days respectively,the primordium density of 0.86/cm~2 and0.45/cm~2,the fruiting density of 83.00/m~2 and 66.00/m~2,the fresh fruiting yield of 791.83 g/m~2 and 707.67g/m~2,and the dry-wet ratio of 10.41%and10.18%.4.Effects of field cultivation of Morchella on soil microbial diversityField cultivation of Morchella had different effects on soil physicochemical properties,bacterial and fungal diversity.2523 bacterial OTUs and 1803 fungal OTUs were sequenced.Flavobacterium was the dominant bacteria and Curvularia was the dominant fungus in the ridging stage.Sphingomonas was the dominant bacteria and Morchella was the dominant fungus in the frosty period.Pseudomonas was the dominant bacteria and Morchella was the dominant fungus in the fruiting stage Sphingomonas was the dominant bacteria and Mortierella was the dominant fungus in field cultivation,the contents of N,P,K and p H were positively correlated with the composition of bacterial community,while the contents of p H,SOM,K and P were positively correlated with the composition of fungal community.