Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts
Doctoral Thesis
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| Định dạng: | Dissertation |
| Ngôn ngữ: | en_US |
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Gottfried Wilhelm Leibniz Universität Hannover
2023
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| Những chủ đề: | |
| Truy cập trực tuyến: | https://scholar.dlu.edu.vn/thuvienso/handle/DLU123456789/115616 http://dx.doi.org/10.15488/9043 |
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| Thư viện lưu trữ: | Thư viện Trường Đại học Đà Lạt |
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| id |
oai:scholar.dlu.edu.vn:DLU123456789-115616 |
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dspace |
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Thư viện Trường Đại học Đà Lạt |
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Thư viện số |
| language |
en_US |
| topic |
Juglans x intermedia Micropropagation Endophytes |
| spellingShingle |
Juglans x intermedia Micropropagation Endophytes Phạm, Ngọc Tuân Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts |
| description |
Doctoral Thesis |
| author2 |
Winkelmann, Traud |
| author_facet |
Winkelmann, Traud Phạm, Ngọc Tuân |
| format |
Dissertation |
| author |
Phạm, Ngọc Tuân |
| author_sort |
Phạm, Ngọc Tuân |
| title |
Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts |
| title_short |
Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts |
| title_full |
Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts |
| title_fullStr |
Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts |
| title_full_unstemmed |
Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts |
| title_sort |
micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts |
| publisher |
Gottfried Wilhelm Leibniz Universität Hannover |
| publishDate |
2023 |
| url |
https://scholar.dlu.edu.vn/thuvienso/handle/DLU123456789/115616 http://dx.doi.org/10.15488/9043 |
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1779418613023768576 |
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oai:scholar.dlu.edu.vn:DLU123456789-1156162023-10-05T16:57:08Z Micropropagation and identification of bacterial endophytes in interspecific hybrid walnuts Phạm, Ngọc Tuân Winkelmann, Traud Juglans x intermedia Micropropagation Endophytes Doctoral Thesis Species and hybrids belonging to the genus Juglans, e. g., J. regia and J. nigra x J. regia (= J. x intermedia), deliver highly valuable timber that achieves high prices on international markets. Therefore, the propagation of ortets with outstanding quality for later use in silvicultural programs or plantation forestry is of great interest. Because autovegetative propagation of Juglans is difficult to be applied, in vitro culture techniques could enable the production of high-quality clones. However, the Juglans genus is largely recalcitrant in terms of micropropagation. The reasons for the difficulties include (1) the mature state of the ortets, (2) the general presence of endophytes, probably already in zygotic embryos (3) the slow growth in vitro resulting in low propagation rates, and (4) difficulties in rooting of the microcuttings. Thus, the aim of this study was to develop a micropropagation protocol for a large-scale production of a wide range of J. x intermedia genotypes for later testing and selection of outstanding clones for a multiclonal variety of J. x intermedia. A second objective was the isolation and characterization of endophytic bacteria from in-vitro material which could help to improve micropropagation techniques of Juglans clones and the plantlet quality. Interspecific hybrid walnut genotypes of the F1 offspring originating from open pollination of a single hybridogenic J. nigra tree in the nursery of Anton Schott were identified using DNA markers (simple sequence repeats = SSRs). In total, 55 Juglans hybrid genotypes, established in vitro from embryo axes, were propagated using an optimized tissue culture process with high propagation and rooting rates and also simple acclimatization. The best shoot elongation and production of new axillary shoots was achieved with 4.4 μM BA and 0.2 μM IBA in Rugini (Rugini 1984) and DKW (Driver and Kuniyuki 1984) media, resulting in clone-depending propagation rates from 2.5 to 5.4 per subculture. The optimal gelling agent for shoot cultures was Kobe agar. The highest rooting percentages (50 to 73%) were obtained with a two step rooting protocol (1. induction phase in DKW medium with 12 μM IBA within five days in darkness; 2. root expression under light in a mixture of a gelified ¼-concentrated DKW medium and vermiculite). The survival rates after the acclimatization were 75 to 93%. To obtain information about the genetic diversity of the J. x intermedia offspring, population genetic parameters were analyzed for the overall progeny and the contributing pollen and compared to reference data sets. The results of paternity analyses were discussed regarding potential mating preferences of this particular hybridogenic J. nigra tree. Bacterial endophytes in Juglans in vitro shoot cultures were analyzed using two different methods: (1) With a culture-dependent approach eight morphologically varying isolates were detected by 16S rRNA sequencing. The findings include Moraxella sp., Bre-vundimonas sp., Acinetobacter sp., Pseudomonas sp. and Roseomonas sp. (2) With a culture-independent approach seventeen libraries were established from an amplified 16S rRNA fragment from 51 plant DNA extracts and analyzed using Illumina MiSeq se-quencing. More than 85% of the total population of the bacteria was detected in all analyzed samples, some of which are known as plant growth promoting bacteria, such as Pseudomonas sp., Erwinia sp., Burkholderia sp., Pelomonas sp., and Sphingomonas sp. The genus Moraxella sp. was identified in the genotypes with higher propagation rates. This finding is a first step towards future inoculation experiments to prove the proposed beneficial effects during micropropagation of Juglans genotypes. 2023-04-10T21:51:02Z 2023-04-10T21:51:02Z 2017 Dissertation https://scholar.dlu.edu.vn/thuvienso/handle/DLU123456789/115616 http://dx.doi.org/10.15488/9043 en_US application/pdf Gottfried Wilhelm Leibniz Universität Hannover |