| Gardenia jasminoides is a dry and mature fruit of Gardenia jasminoides Ellis,a genuine medicinal material in Jiangxi Province.It has bitter and cold taste.It has the functions of purging fire and removing irritation,clearing heat and dampness,cooling blood and detoxifying toxins.It is a co mmon medicinal material for clinical treatment of fever and upset,jaundice and urine,bloody gonorrhea and astringent pain,hemorrhagic fever and vomiting,eye edema and sore,sprain and contusion.As a natural pigments,Gardenia pigments are more and more popular and have broad market prospects.Gardenia jasminoides is planted in most provinces of China.Brown spot is a co mmon leaf disease in Gardenia cultivation.It occurs seriously in China,which leads to the decline of gardenia fruit yield and quality.It poses a serious threat to the growth of gardenia,causing huge economic losses and hindering the rapid development of traditional Chinese medicine.Therefore,the study of Gardenia brown spot is particularly important.In this study,the pathogen of scorpion brown spot was taken as the research object,and the brown spot disease was isolated and identified by routine tissue separation method.The changes of physiological and biochemical indexes during the process of brown leaf spot infection of scorpion leaves were studied.The trend of physical and chemical indicators under disease stress,followed by research on biocontrol bacteria of brown spot disease.The purpose of this study was to clarify the pathogens of brown spot disease of scorpion,study the trend of physical and chemical indicators under the condition of plant diseases,and screen the bacteria that have the preventive effect on the pathogen of scorpion brown spot disease,in order to provide experimental basis for the biological control of brown spot disease.The leaves of typical brown spot of scorpion were used as the research object.The pathogens isolated from the pathogens were isolated and purified.The pathogenic strains of scorpion brown spot disease were identified according to the Koch’s method to observe the pathogenicity.The microscopic morphological characteristics of the strain and the results of the fungal rDNA-ITS sequence were compared and analyzed.The pathogens were identified.The results showed that the pathogenic strains isolated and purified from the leaves of the typical scorpion brown spot disease were cultured in a plate culture dish.In the beginning,there are white air-like villous hyphae,the colony is white,and then gradually deepened into light brown and dark brown.The mycelium is white,branched,and separated under the microscope.The rDNA-ITS sequence analysis results are compared and analyzed in Genbank.The pathogen is Nigrospora oryzae.The leaves of healthy scorpion were infested with the isolated brown spot 2 bacteria,and the activities of CAT,POD,SOD,PPO and PAL in different time periods after 0-72 h of infection were studied to study the infection of scorpion brown spot disease.The changes of physiological and biochemical indexes in the process,the activity of CAT increased continuously at 0-6 h,and decreased slowly after reaching the peak of activity at 6h;the activity of POD continued to increase at 0-12 h,and the activity peaked at 3 h and 12 h,then the activity showed a slow decline.Trend;SOD decreased firstly at 0-3 h,then activity increased continuously at 3 h-12 h,peaked at 12 h,then decreased slowly;PPO increased continuously at 0-12 h,and slowly decreased after 12 h activity peaked;The activity of PAL increased continuously in 0-12 h,and the activity peaked at 12 h,then the activity decreased rapidly after 12-24 h,and then decreased slightly.The results indicate that different enzymes act upon resistance to pathogen invasion or at the same time or at different times,resulting in resistance.The scorpion rhizosphere soil was selected,and the bacteria were isolated and screened by soil serial dilution method.The bacteria were initially screened by the plate sputum method for the inhibition of the brown spot disease of the scorpion,and the bacteria with the inhibitory effect were prepared to prepare the fermentation broth and mixed with the PDA.After being uniformly inoculated,the brown spot pathogen was inoculated,and the inhibition rate was measured again.Finally,the fermentation liquid was taken for the leaf control rate test.The results showed that the strain YN-1 had a high control rate,and its control efficiency was as high as 62.50%.Molecular identification was performed,and the 16 S rDNA sequence results were compared in the GenBank database to determine that the strain was Pseudomonas putida. |
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