An isozyme analysis of the induced resistance response to Fusarium wilt of watermelon incited by incompatible vascular wilt Fusaria /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | In an attempt to investigate possible biological control strategies for the watermelon wilt pathogen and further elucidate resistance mechanisms in watermelon to Fusarium wilt, research was initiated in the following areas: 1) induced resistance in watermelon to Fusarium wilt and corresponding peroxidase isozyme markers, 2) the analysis of xylem fluid protein and its ability to inhibit microconidial germination, and 3) isozyme variation among Fusarium isolates. Watermelon cultivars tray dipped in a 10^6 conidia/ml suspension of Fusarium oxysporum f. sp. niveum races 0 and 1, and F. o. f. sp. cucumerinum were significantly protected from the virulent F. o. f. sp. niveum race 2, also applied at 10^6 microconidia/ml. Additionally, when leaves of the induced plants were inoculated with a 10^5 lesions occurred on the plants with induced roots. This implies that the induction of resistance was systemic and non-specific. Peroxidase leaf isozymes corresponding to the induction process were observed on IEF-PAGE and Native-PAGE. Differential proteins were observed among watermelon cultivars in xylem fluid. When the xylem fluid was incubated for 6 hr with microconidia and then plated onto media, inhibition of microconidia germination was observed. The inhibition was xylem concentration dependent, but independent of watermelon cultivar source or isolate of Fusarium oxysporum, indicating that the xylem fluid may contain a general mechanism of resistance that the compatible pathogen overcomes. The active component appears to be a highly stable moiety with proteinaceous characteristics. Isozyme patterns of fusaria used throughout the study were compared on IEF-PAGE and Native-PAGE. The electrophoretic techniques distinguished between F. o. f. sp. niveum races, F. oxysporum ff. sp. and F. solani. Race 2 of F. o. f. sp. niveum was phenetically closer to F. o. f. sp. cucumerinum than to the other two F. o. f. sp. niveum races. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Plant Pathology." |
| Physical Description: | xiv, 156 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 132-148). |