The Characteristic Indexes Change Of The Dictyophora Rubrovalvata Spawn Mycelia In The Process Of Aging And Redness

Dictyophora rubrovalvata M.Zang is the most characteristic and advantage edible fungus in Guizhou.In China,the wild Dictyophora rubrovalvata is mainly distributed in the humus soil of Guizhou,Yunnan,Sichuan,Zhejiang.Dictyophora rubrovalvata was first cultivated successfully in zhijin county,guizhou province.Zhijin obtained the Dictyophora rubrovalvata national geographical symbol certification,and was awarded the title of "the hometown of Dictyophora rubrovalvata in China" by China edible fungus association.At present,artificial cultivation of Dictyophora rubrovalvata has already radiated the whole province of Guizhou.However,in the production of spawn often appear the phenomenon of mycelium redness and aging,which seriously affects the yield and quality.This research through to study the characteristics of vegetative mycelium morphological,physiological and biochemical,and applied the molecular marker technology,in order to understand the ageing characteristics,and provides a theoretical basis for the establishment and application of the production technology and quality standard of the spawn.The main results are as follows:(1)The vegetative mycelium was cultured for 90 days in the sawdust culture medium,10 days was taken as a period of age.Macroscopical and microscopic observation of each period of the vegetative mycelia,and and taked the mycelium of different age groups to the culture medium to compare the germination time and growth.The results show that the mycelium is white and sturdy in 10 to 30 days,the mycelium structure is complete and single and the cell wall is smooth and the cytoplasm is evenly distributed.Starting from the 40 day,the mycelia gradually turn red and collapse from the inner ring to the outer ring,the surface of the mycelium attached to the granular material,the cell wall is rough and the cytoplasm is unevenly distributed.The granular material increased of the mycelium surface and some mycelial cell walls began to dissolve in 50 to 60 days.In 70 to 80 days,the mycelium did not appear linear,and the cytoplasm and cell wall began to dissolve.While 90 days,the mycelium dissolved completely,and no complete line like mycelium appeared.It was found that the time of germination was longer with the increase of the age of bacteria,and the growth rate of the mycelium of different ages was decreased.(2)The extracellular enzymes activity of the different growth period of mycelia was determined by enzyme kit for,the results showed that laccase,neutral xylanase,cellulose enzyme,superoxide dismutase,polyphenol oxidase,catalase and peroxidase were activity.The laccase and PPO enzyme activity gradually decreased with the growth of mycelium,and the fluctuation amplitude was small.The overall activity of CL,NEX,and SOD enzyme showed a change rule of the first ascending and then descending,while the variation trend of CAT and POD enzyme activity is diverse,without stable regularity.The laccase enzyme activity was the maxima,followed by CL,which was the key enzyme of mycelium growth,and the lignin and cellulose were the main nutrients for mycelium growth.The activity of NEX enzyme is very low,the results showed that the utilization rate of Dictyophora rubrovalvata to hemicellulose was very low.Therefore,the substrate rich in lignin and cellulose should be added in the production of spawn.By analyzing the correlation between enzyme activity and the age,laccase,PPO and SOD enzyme activities were significantly correlated with the age,which can be used as a physiological and biochemical index for the aging of mycelia.(3)Through the c DNA-SRAP technique to screen differentially expressed gene fragments from two stages of 40 days and 90 days growth mycelia,and apply bioinformatics method analyze and predict the gene function of specific fragments.45 differentially expressed fragments were obtained from the Ageing mycelium.40 fragments TA clones were successfully cloned,of which 16 were specific and 11 were identified by Gen Bank ratio.(1)Seven etabolic degradation related genes include Nonspecific phospholipase,aspartic acid protease,glycosyltransferase and so on.(2)Short chain dehydrogenase redox gene.(3)Cytochrome receptor factor gene.(4)Temperature sensitive mutant gene.(5)Microtubule protein gene.Therefore,the essence of mycelium aging and discoloration is the result of multiple gene expression regulation.