Artemisia annua L. is a common type of wormwood that grows throughout the world. Artemisinin, a terpene compound in A. annua, has recently been recognized as the most promising antimalaria drug. Artemisinin and other types of terpenoids are synthesized and accumulated in glandualr trichomes that appear on the surface of leaf, stem and flower bud. To identify new genes involved in artemisinin biosynthesis and trichome function in A. annua, a normalized glandular trichome cDNA collection was sequenced by Roche GS FLX pyrosequencing system. Two sequencing runs generated totally 85M nucleotides which were further assembled into 190,377 unigenes (42,678 contigs and 147,699 sigletons). Putative functions were assigned to the unigenes based on Blast search against GeneBank database. Many terpene biosynthesis pathway genes were identified from the pyrosequencing ESTs. Together with other identified A. annua terpene pathway genes, a global view of terpene biosynthesis in glandular trichomes of A. annua were re-established. Meanwhile, a WD repeat protein, AaWD40, which show high amino acid sequence similarity with its Arabidopsis ortholog, AtTTG1 (AT5G24520) was identified. To investigate the functional relevance of AaWD40 to its Arabidopsis counterpart, genetic complementation test using Arabidopsis mutants was conducted. When AaWD40 was transformed into Arabidopsis transparent testa glabrous1 (ttg1-1) mutant, the anthocyanins and proanthocyanidin (PAs) production in seeds were restored, and the trichomeless phenotype of ttg1-1 mutant was rescued. In addition, over-expression of AaWD40 and AtTTG1 modulated the expression of WUS and CLVs genes which are required to maintain the stem-cell niche of Arabidopsis shoot apex. Transcriptomic profiling of transgenic Arabidopsis over-expressing AaWD40, TTG1, or ttg1-1 mutant revealed lists of genes modulated by these two WD40 genes homologue and gene ontology (GO) analysis suggested that the top-ranked categories are defense, stress response and developmental programme. We hypothesize that WD40 repeat protein act as a crucial regulatory factor in a wide variety of cellular functions in A. thaliana. / Wang, Wei. / Advisers: Guo Dianjing; Jiang Liwen. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 82-105). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344714 |
| Date | January 2010 |
| Contributors | Wang, Wei, Chinese University of Hong Kong Graduate School. Division of Life Sciences. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xii, 105 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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