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内生菌による窒素固定システムがサトウキビに定着する仕組みの解明
http://hdl.handle.net/10458/978
http://hdl.handle.net/10458/97804a2b775-cd3b-464d-a6ff-8ced8f624174
| 名前 / ファイル | ライセンス | アクション |
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DT_JoycePriscaNjoloma.pdf (8.1 MB)
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| Item type | 学位論文 / Thesis or Dissertation(1) | |||||
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| 公開日 | 2007-11-26 | |||||
| タイトル | ||||||
| タイトル | Establishment Mechanism of Nitrogen Fixing System by Endophytic Bacteria in the Japanese Sugarcane Plant | |||||
| 言語 | en | |||||
| タイトル | ||||||
| タイトル | 内生菌による窒素固定システムがサトウキビに定着する仕組みの解明 | |||||
| 言語 | ja | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_46ec | |||||
| 資源タイプ | thesis | |||||
| 著者 |
Njoloma, Joyce Prisca
× Njoloma, Joyce Prisca |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Sugarcane (Saccharum spp. L.) is one of the most important agricultural crops whose products are both for export and domestic consumption in most of the tropical and subtropical countries of the world. Several recent studies have confirmed that biological nitrogen fixation by endophytic bacteria contributes significantly to the nitrogen nutrition of sugarcane. Endophytic diazotrophic bacteria, which have been isolated in association with sugarcane plants, includes Acetobacter diazotrophicus and Herbaspirillum spp. In this research work, the main objective was to study the mechanisms involved in the establishment of nitrogen fixing system in sugarcane plant through the investigation of the mode of infection and mechanism by which the endophytic diazotrophic bacteria colonizes sugarcane after inoculation. Herbaspirillum spp. B501gfp1 (B501gfp1), an isolate from wild rice was used as source of inoculum to investigate the interaction between nitrogen-fixing endophytic bacterium and micropropagated sugarcane plants under aseptic and non-sterile conditions. In the first place an investigation was carried out to detect if the green fluorescence protein's expression from B501gfp1 could be distinguished from the sugarcane tissue's background fluorescence. B501gfp1 bacterial cells were spot inoculated on to sugarcane tissues from 5 month-old sterile micro-propagated plants. Stem tissues and leaf sections mounted on glass slides were directly inoculated with a single touch using the tip of a syringe previously dipped into the inoculum containing 10(8) bacterial cells ml(-1). It was observed that GFP fluorescence could be easily distinguished in the stem than in the leaf tissues. However, the brightness level of the fluorescence varied with time as a result of fluctuations in the bacterial cell density. The presence of chloroplasts in the leaf tissues of sugarcane requires the use of bright GFP variants when monitoring bacteria-plant interactions using gfp labeled bacteria. In a study under sterile condition, two Japanese sugarcane plant cultivars (cvs) NiF8 and Ni15 were inoculated using B501gfp1 in 2 inoculum doses of 10(8) and 10(2) bacterial cells ml(-1) suspension. The results obtained showed that bacterial cells colonized both the root and stem tissues, and colonization was apparent in the intercellular spaces. Higher bacterial numbers detected in plant tissues corresponded to the higher inoculum concentration treatment. Bacterial numbers also varied between the 2 cultivars with the higher values determined in cv. Ni15. Colonization ability of B501gfp1 in the presence of indigenous endophytes in sugarcane under non sterile condition was also carried out using the two inoculum concentrations (10(2) and 10(8) bacterial cells ml(-1)) and in cv NiF8 only. Internal tissue colonization was observed in plants inoculated with both the 10(2) and 10(8) B501gfp1 bacterial cells ml(-1) inoculum concentrations. However, extensive colonization and higher bacterial numbers were determined in the basal stem tissues of plants inoculated with the 10(8) bacterial cells ml(-1). Infection and establishment of the bacteria in the plants varied with respect to the inoculation technique. In the sterile plants inoculated with intact roots and basal stem, more bacteria were detected in the root tissues with the lateral root junctions as the main entry points. However, in some instances internal tissue colonization was observed to have occurred through intact root surfaces. On the other hand, plants which were inoculated with their stem bases bearing cut openings under non-sterile condition had more bacteria colonizing the stem tissues with dense establishments in the vascular bundle tissues. It can therefore be concluded that the mode of infection and subsequent establishment mechanism in the internal tissue is facilitated by the inoculation technique and availability of entry points. This study also provides evidence for non-specificity of host plant among endophytes since Herbaspirillum spp. B501gfp1, a rice isolate could colonize sugarcane plant tissues. |
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| 言語 | en | |||||
| 内容記述 | ||||||
| 値 | 鹿児島大学大学院連合農学研究科博士論文 | |||||
| 内容記述 | ||||||
| 言語 | ja | |||||
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| 出版タイプ | AM | |||||
| 出版タイプResource | http://purl.org/coar/version/c_ab4af688f83e57aa | |||||
