| Lycium barbarum L.is a unique medicinal plant in the Northwest China.The study of Lycium barbarum L.at home and abroad is focused on the research of its chemical composition,stress resistance,antioxidant resistance and its related functional products.However less research in its function of endophytic fungi.This study take the Lycium barbarum L.in Ningxia as the research object,and based on the diversity and distribution of endophytic fungi,the plant pathogenic fungi were used as the target bacteria to screen the highly active antagonistic strains and explore their potential for antibacterial,antibiotic and heavy parasitism.Screen the chitinase and β-1,3-glucanase strains to explore their production conditions.It can be initially revealed its mechanism of disease resistance by making the host colonies to be infected by endophytic fungi,and determine the effects of endophytic fungi on plant growth,defense enzyme activity.The results are as follows:1.The author use the way of tissue separetion to separate the healthy medlar,then analyze and identify bacterial strain using morphological features and rDNA-ITS sequence.The results shows that the 363 samples of endophytic fungi strains were isolated from Lycium barbarum L.,these strains belong to 14 genera,including Alternaria,Thielavia and Aspergillus.Rrespectively the number of isolates were 46%,14%and 13%.Each organ of the lycium has an endogenous mycogene distribution,with the largest diversity within stems,it is 0.88,and the maximum coefficient of similarity is fruit and stem.The separation rate and distribution frequency of endogenous fungi show that there is difference in the distribution of different endogenous medlar.2.Using Colletotrichum gloeosporioides and four kinds of common plant pathogenic fungi as target bacteria,using melamine in confrontation and spore germination inhibition test,the author test the antagonism between 121 strains of endophytic fungi.The results showed that the strain NQ3GF1,NQ7GF3 and NQ8YF3 are highly active in antagonism,and NQ7GF3 is the best of them antibacterial belt width up to 9.96 mm.Strain NQ3GF1 and NQ4YF11 broad-spectrum antibacterial activity,the test of 5 kinds of germs,there are different degrees of inhibition.The strain NQ3GF1 and NQ7GF3 were found to have better inhibitory effect on the spore germination of medlar anthrax,and the inhibition rate was more than 75%after 6 hours.The results showed that the strains of NQ3GF1 and the bacterium of medlar anthrax were entangled and penetrating,and can successfully colonizing the roots of the medlar.Finally the author find that the strains NQ3GF1,NQ7GF3,and NQ8YF3 are respectively the Alternaria tenuissima,the Cladosporium uredinicola,and the Coniolariella gamsii through the help of morphological and molecular biological tests.3.The author used the transparent circle method to screen chitnase and β-1,3-glucanase of the 6 strains of highly active medlar antagonism endophytic fungi and find two strains could produce chitnase and β-1,3-glucanase at the same time and strains NQ3GF1 and NQ7GF3,including strain NQ3GF1 have the highest enzyme activity,its transparent circle diameter up to 6 mm.By liquid culture method exploring NQ3GF1 thick enzyme fluid found that the effect of two kinds of crude enzyme liquid of Colletotrichum gloeosporioides Pena.the bacteriostasis of belt width not less than 10 mm,expand the antibacterial spectrum of pathogenic bacteria also has good antibactefial effect on other five kinds of common plant;To strain NQ3GFi enzyme production conditions of the research shows that when the carbon source(poria cocos powder or colloidal chitin)was 0.6%,the nitrogen source is peptone,initial pH value between 6～8,25 ℃ shaking for 6 days,the chitnase and β-1,3-glucanase has the highest activity.4.By microscopic observation and tie-back test of the endophytic fungi of Lycium barbarum L.NQ3GF1 infect colonization in medlar root ministry,and the growth of the host,and the influence of defense enzymes,the results showed that the hypha was formed into a network structure in the root after 24～48 hours,and after 72 hours,the mycelium penetrated the epidermis into the root of the marrow.Concentration less than 30%of inactivated hyphae fermentation medium and the concentration less than 50%of Chinese wolfberry somaclone of live bacteria fermented liquid,it has a promoting effect on potted seedlings growth,when the concentration is higher than the concentration,it would restrain the growth of the plant.The endogenous fungi NQ3GFi increased the resistance of the seedlings to 75.27 percent,and was three times as large as those that were untreated.Strain NQ3GF1 fermented liquid within 3～12 days after inoculation,the concentration of POD enzyme activity was increased in treatment group,reached the highest in 9 days and 6 days to 22.41 U/g FW,5.61 U/g FW,POD,PPO,and SOD are lower than the control group. |
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