| Proso millet is widely cultivated in northern my country and the cultivation area is huge.The corresponding proso millet straw resources are also very rich.However,as an important renewable resource,it has not been effectively used,and most of them are randomly discarded in the fields and burned in the open.Cause agricultural non-point source pollution,affect soil quality,pollute the local natural environment,and easily cause fires,seriously endangering people’s lives and property.In recent years,straw-based materials technology has been applied to the production of edible mushrooms more and more.The nutrients contained in the proso millet straw make it a raw material for edible mushrooms cultivation.Pleurotus ostreatus has a stronger ability to decompose straw than other edible mushrooms,so in this study,Pleurotus ostreatus cell engineering strains with the advantage of decomposing proso millet straw were selected by mutagenic breeding of Pleurotus ostreatus.It is expected to better realize the resource development of proso millet straw,reduce agricultural non-point source pollution,promote the development of ecological agriculture in the cause of accurate poverty alleviation,increase farmers’ income,and provide new technical support for the realization of circular economy.In this paper,the mutation breeding of Pleurotus ostreatus original strain Xin Heda P-2was carried out by using MPMS technique,and 60 s was determined as the best mutagenic time for Pleurotus ostreatus Xin Heda P-2.At this time,the mycelium mutation rate was higher,and a total of 367 strains were obtained after repeated mutagenesis for 60 s.Through the preliminary screening antagonistic test,a total of 39 mutagenic strains had obvious antagonistic reaction with the original strain.After a series of re-screening tests,including comparison of mycelial growth rate,comparison of extracellular enzyme activity and comparison of biological efficiency,it was determined that the characters of mutagenic strains PA5,PA22,PA36,PA61 and PA143 were better than the original strain,and the characters of strain PA36 were the best.The authenticity of the selected excellent strains PA5,PA22,PA36,PA61,PA143 and the original strain were identified by ISSR molecular marker technology.The results showed that the genetic similarity coefficient variation range between the five excellent strains and the original strain was 0.620～0.885,indicating that there were different degrees of differences between the five excellent strains and the original strain,and the screened mutagenic strain PA36 with the best character was named Xin Heda P-3.The mycelium of Xin Heda P-3 is white and dense and grows vigorously in the proso millet straw substrate,and large-scale cultivation demonstration has been carried out in the scientific and educational demonstration base,and the effect is good.It is preliminarily determined that the mutagenic strain Xin Heda P-3 is the dominant strain suitable for decomposing proso millet straw.In this paper,by comparing the mycelial growth rate of Xin Heda P-3 in different original medium formulations,it was determined that the most suitable original medium formula for Xin Heda P-3 was 88% of wheat grain,10% of proso millet straw and 2% of lime.By comparing the mycelium growth rate and biological efficiency of Xin Heda P-3 in different proso millet straw cultivation medium,it was determined that the optimal culture medium formula of Xin Heda P-3 was 53% of proso millet straw,28% of corncob,17% of wheat bran and 2% of lime.under this formula,the mycelium growth rate of Xin Heda P-3was 8.62 mm/d,and the biological efficiency was 123.58%.Through the cultivation experiment of Pleurotus ostreatus under the forest in Chicheng area of Zhangjiakou,the results show that the biological efficiency of Pleurotus ostreatus P-3 under the forest can reach 112.47%.In this paper,the contents of dietary fiber,protein,polysaccharides,total flavonoids,total sterols and polyphenols in the fruiting bodies of 5 excellent strains and the original strains cultivated under the substrate of proso millet straw were compared with commercial Pleurotus ostreatus fruiting body.the results showed that the contents of six components in the fruiting bodies of Pleurotus ostreatus strains Xin Heda P-3,PA5 and PA143 were higher than those of commercial Pleurotus ostreatus.The contents of dietary fiber,polysaccharides,total flavonoids,total sterols and polyphenols in Xin Heda P-3 fruiting body were the highest.According to the comprehensive analysis,the quality of related components in Pleurotus ostreatus Xin Heda P-3 fruiting body was the best,which was significantly better than that of commercial Pleurotus ostreatus and starting strain. |
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