Identification and evaluation of endophytes from tropical tuber crops against colletotrichum gloeosporioides (penz.) sacc. causing anthracnose in greater yam (dioscorea alata L.)
By: Shahana, N.
Contributor(s): Jeeva, M L (Guide).
Material type:
BookPublisher: Vellayani Department of Plant Biotechnology, College of Agriculture 2018Description: 88p.Subject(s): Plant BiotechnologyDDC classification: 660.6 Online resources: Click here to access online Dissertation note: BSc-MSc (Integrated) Abstract: Greater yam (Dioscorea alata) is recognized as a major tuber crop in tropical countries. One of the main constrain in greater yam production is anthracnose disease which is caused by a fungus Colletotrichum gloeosporioides. Several chemical fungicides, resistant varieties and biological control has been adopted for managing the disease and Still these methods are not found to be much effective in controlling the disease. Endophytes are microorganisms, both fungi and bacteria reside inside the host without causing any apparent harm to the host and they possess various potential funtions in host plant like growth promotion, disease control etc. In this study, the potential endophytes both bacteria and fungi against Colletotrichum gloeosporioides causing anthracnose in greater yam was screened and identified. The endophytes from different tropical tuber crops were utilized for screening against the pathogen by dual culture method. A total of 139 endophytes isolated, 37 bacterial and 37 fungal endophytes were found to be morphologically distinct and were selected for screening. From that, three bacterial endophytes with antifungal index of 88.6, 85.7 and 84.6% and four fungal endophytes with antifungal index of 67.1, 55.7, 49.3 and 45.3% were obtained. These endophytes were identified using molecular methods as bacterial endophytes were Bacillus cereus, Bacillus subtilis, and Bacillus subtilis., the fungal endophytes as Penicillium citrinum, Phanerochaete australis, Curvularia pseudobrachyspora and Diaporthe batatas repectively. The fungal endophytes were found to be less potent when compared to bacterial endophytes. Specific primers were designed based on the common regions of potent bacteria and its colonization in tissue culture plants were confirmed using these species-specific primers. The pot trial studies in glass house and in open condition proved that Bacillus cereus followed by Bacillus subtilis had potential activity in managing the anthracnose disease as well as growth promotion activity. In glass house as well as open condition, Bacillus cereus showed a disease intensity of 11.6 % with a score of 2. It could be a best biointensive method to manage anthracnose disease in greater yam.
| Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Theses
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KAU Central Library, Thrissur Theses | Reference Book | 660.6 SHA/ID (Browse shelf) | Not For Loan | 174430 |
BSc-MSc (Integrated)
Greater yam (Dioscorea alata) is recognized as a major tuber crop in tropical countries. One of the main constrain in greater yam production is anthracnose disease which is caused by a fungus Colletotrichum gloeosporioides. Several chemical fungicides, resistant varieties and biological control has been adopted for managing the disease and Still these methods are not found to be much effective in controlling the disease. Endophytes are microorganisms, both fungi and bacteria reside inside the host without causing any apparent harm to the host and they possess various potential funtions in host plant like growth promotion, disease control etc. In this study, the potential endophytes both bacteria and fungi against Colletotrichum gloeosporioides causing anthracnose in greater yam was screened and identified. The endophytes from different tropical tuber crops were utilized for screening against the pathogen by dual culture method. A total of 139 endophytes isolated, 37 bacterial and 37 fungal endophytes were found to be morphologically distinct and were selected for screening. From that, three bacterial endophytes with antifungal index of 88.6, 85.7 and 84.6% and four fungal endophytes with antifungal index of 67.1, 55.7, 49.3 and 45.3% were obtained. These endophytes were identified using molecular methods as bacterial endophytes were Bacillus cereus, Bacillus subtilis, and Bacillus subtilis., the fungal endophytes as Penicillium citrinum, Phanerochaete australis, Curvularia pseudobrachyspora and Diaporthe batatas repectively. The fungal endophytes were found to be less potent when compared to bacterial endophytes. Specific primers were designed based on the common regions of potent bacteria and its colonization in tissue culture plants were confirmed using these species-specific primers. The pot trial studies in glass house and in open condition proved that Bacillus cereus followed by Bacillus subtilis had potential activity in managing the anthracnose disease as well as growth promotion activity. In glass house as well as open condition, Bacillus cereus showed a disease intensity of 11.6 % with a score of 2. It could be a best biointensive method to manage anthracnose disease in greater yam.
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