부산대학교 도서관

In an attempt to develop mycofumigant biofungicide for the control of storage and soil-borne diseases,1. A total of 75 fungal isolates of endophytic fungi were obtained from healthy tissue samples of red pepper and trees of Lauracerae and then tested for their fumigant activaties against a phytopathogenic fungus Botrirys cinerea. Among them, only two fungi designated of CF016 and EF069, which were isolated from the stems of cinnamon (Cinnamomum loureirii) and stems of red pepper (Capsicum annum L.), respectively, produced antifungal volatile compounds. CF016 and EF069 were identified as Nodulisporium sp. and Oxyporus latemarginatus, respectively, their morphological characteristics and ITS-5.8S ribosomal DNA sequences.2. Mycofumigation plate assays by volatile compounds of EF069 and CF016 were performed to investigate for their fumigant activities against mycelial growth of A. alternata, B. cinerea, C. gloeosporioides, F. oxysporum, M. grisea and R. solani. Both fungi inhibited th mycelial growth of all of the plant pathogenic fungi tested. O. latemarginatus EF069 strongly suppressed the mycelial growth of M. grisea and R. solani by 85% and 75%, respectively. Nodulisporium sp. CF016 was highly effective to C. gloeosporioides and B. cinerea with inhibitory activities of 76% and 72%, respectively.3. In vivo disease control efficacy of against apple gray mold, radish damping-off and Rhizoctonia disease of Phalenopsis sp. were evaluated. The volatile gas produced by O. latemarginatus EF069 effectively controlled gray mold on apples as compared with non-exposed control and Rhizoctonia disease of Phalenopsis sp. EF069 reduced the development of Rhizoctonia disease caused a 17% increase in number of leaves. In addition, EF069 suppressed the development of Chinese cabbage clubroot by 33% and radish damping-off by 85% in a grwoth chamber.4. In field trials, EF069 was highly effective to control the clubroot disease as compared with untreated controls. The disease control values were 82% in the highly infected field and 79% in the lowly infected field. In addition, the EF069 produced 1.8 times higher yields of Chinese cabbage than untreated control in the highly infected field and 2.6 times higher in the lowly infected field. To examine the colonization of EF069 in roots of Chinese cabbage the roots inoculated with EF069 were observed under a fluorescent microscopy. Fluorescent microscopy of cross sections of roots showed that the hyphae of EF069 extended into the inner cortical cells and colonized hyphae.5. To examine the production of nonvolatile antifungal metabolites by EF069 PDA and PDB of EF069 were tested in in vitro and in vivo bioassays. As the result, its antifungal activity was not found in the cultures. This indicated that EF069 did not produce nonvolatile antifungal compounds.6. In order to identify volatile antifungal compounds produced by O. latemarginatus EF069, the vapour phase of solid cultures of EF069 was analyzed by GC-MS. As the result, a peak was appeared in total ion chromatogram and its mass spectrum indicated that the molecular weight might be 166 amu. The determination of the chemical structure of compound is in progress.Further studies on the large scale fermentation, formulation and field trials in various field conditions are necessary for the development of new microbial fungicide using O. latemarginatus EF069 producing volatile antifungal compounds.