Identification Of Pathogenic Fungi On Ornamental Plants In UESTC And The Potential Of Endophytic Fungi As Biocontrol Agents Against Pathogens

With the continuous expansion of the planting area and frequent circulation of ornamental plants,fungal diseases are becoming increasingly severe.Fungal diseases greatly reduce the ornamental,medicinal,and edible value of plants.This study identified fungal diseases on ornamental plants at the Qingshuihe Campus of the University of Electronic Science and Technology.164 strains were isolated from diseased tissues of five ornamental plants,including geraniums in the Geraniaceae family,wild roses and pears in the Rosaceae family,golden chrysanthemums and zinnia elegans in the Compositae family.17 diseases causing and 6 diseases associated fungi were identified through morphology and molecular sequence data.The identified pathogenic fungi cover11 genera and 22 species,including Alternaria,Botrytis,Colletotrichum,Diaporthe,Epicoccum,Fusarium,Neofusicoccum,Neopestalotiopsis,Nigrospora,Pestalotiopsis and Pseudopestalotiopsis;The fungal diseases involved include spot disease,wilt disease,anthracnose,Fusarium wilt disease,and gray mold.The pathogenicity of pathogenic fungi on the host was evaluated.The isolated and purified pathogenic fungi were inoculated on healthy plants,and the pathogenicity of the fungal diseases was determined by the size of the area of disease symptoms.The specific research results are as follows:The pathogenic fungus for geranium white spot disease is Ni.oryzae,the pathogenic fungus for wilt disease is Pe.kenyana,the pathogenic fungus for anthracnose disease is C.scovillei,and the pathogenic fungus for gray mold disease is B.cinerea.The five pathogenic fungi of wild rose spot disease are Pe.trachycarpico-la,D.phoeniicola and C.boninense,Neop.terricola and B.cinerea,D.sojae,E.mezzettil,and the pathogenic fungi of leaf blight disease are Neof.yunnanense.The pathogenic fungus of pear spot disease is E.mezzettil.The two fungi associated with the disease are Al.alternata and Pe.oryzae,the pathogenic fungus for leaf blight is D.acuta,the pathogenic fungus for anthracnose is C.siamense,and the pathogenic fungus for wilt is F.graminearum.The pathogenic fungus of golden chrysanthemum brown spot disease is E.oryzae,and the pathogenic fungus of wilt disease is F.graminearum.The pathogenic fungi of zinnia elegans anthracnose are C.fioriniae,and the four fungi associated with spot disease are F.pernambucanum,E.dendrobii,Neop.saprophytica,and Ps.theae,respectively.Among them,Ni.oryzae causes geranium white spot disease,Pe.kenyana causes geranium flower blight disease,Pe.trachycarpicola causes wild rose brown spot disease,Neop.terricola and B.cinerea cause wild rose blood red spot disease,and C.fioriniae causes zinnia elegans anthracnose disease are the first reports to the worldwide.After completing the above work,the biological control potential of endophytic fungi obtained from ornamental plants was explored.Three endophytic fungi(Papiliotrema flavescens,Nigrospora oryzae and Arthrinium marinum)obtained from wild roses and pears were subjected to double culture experiments with nine pathogenic fungi obtained from the above identification research work.The growth distance of pathogenic fungi in the double-culture experimental group and the control group was compared,and the inhibition rate of mycelium growth was used to demonstrate the inhibitory effect of endophytic fungi on pathogenic fungi.The results showed that all three endophytic fungi could act as potential biocontrol agents,while Pa.flavescens having the greatest potential,effectively inhibiting the growth of F.graminearum and Pe.kenyana.This study identified the diseases of geraniums,wild roses,golden chrysanthemums,pears,and zinnia elegans in the region,which can provide a basis and suggestions for disease prevention and control strategies of the five ornamental plants.The metabolites produced by the pure culture of the pathogen on the culture medium can be used to study its metabolites and pathogenic mechanisms.The pure culture can also be cultured together with other endophytic fungi as materials for antagonistic experiments.In addition,the three endophytic fungi obtained showed potential as biocontrol agents.