Studies Into the Molecular Genetics of Alkaloid Synthesis in the Genus Nicotiana

Studies Into the Molecular Genetics of Alkaloid Synthesis in the Genus Nicotiana
Author: Kathleen D. DeBoer
Publisher:
Total Pages: 506
Release: 2010
Genre: Nicotiana
ISBN:

Two versions of the QPT gene were isolated (NgQPT1 and NgQPT2) from the genomic library of N. glauca. Both genes are highly homologous throughout their coding regions, and appear capable of encoding full length QPT proteins. However, they contain markedly divergent 5' regulatory regions and intronic regions. NgQPT2 seems to be the predominant transcript in both leaves and roots of N. glauca plants, with the proportion of the NgQPT2 transcript in the total QPT transcript pool, appearing to increase in both tissues in response to apex removal. Fusion of 2.4 kb from the NgQPT2 5' regulatory region to uidA, and transfer into hairy roots and transgenic plants, showed the promoter to be responsive to jasmonate. However, it appears to lack the necessary elements that confer responsiveness to apex removal and leaf based expression in transgenic N. glauca plants. The AP-2 transcription factors, NtORC1 and NtJAP1, which have previously been shown to activate the Nicotiana sylvestris putrescine N-methyltransferase (PMT) promoter (De Sutter et al., 2005), were tested for their ability to activate the N. glauca QPT2 promoter. Using a tobacco cell protoplast transient assay system, NtORC1, but not NtJAP1, was shown to activate the NgQPT2 promoter. The endogenous QPT transcript was also shown to accumulate in N. glauca hairy root lines overexpressing the NtORC1 gene. Previous studies have indicated that the ODC enzyme from Nicotiana glutinosa can decarbonxylate both ornithine and lysine (Lee and Cho, 2001a). To determine whether this enzyme is involved in the synthesis of anabasine in N. glauca, ODC transcript levels were down-regulated by RNAi technology in N. glauca hairy root cultures. ODC transcript down-regulation had very little effect upon anabasine levels, although a decrease in nicotine concentration was observed in many lines. This suggests that lysine decarboxylation, leading to cadaverine and anabasine synthesis, occurs via a different enzyme in this species. As a point of comparison, ODC transcript levels were also down-regulated in N. tabacum hairy root cultures, with a marked decrease in nicotine, and a concurrent increase in anatabine concentrations being observed in a number of lines. One copy of the A622 gene was isolated from the genome of N. glauca. At the onset of this study, a functional role for A622 in alkaloid biosynthesis had not been established. To examine the role of A622 in anabasine biosynthesis, transcript levels were down-regulated in N. glauca plants, via RNAi technology. A substantial reduction in anabasine levels was observed in transgenic plants and their offspring containing the RNAi construct. These results confirm an important role for the A622 enzyme in the synthesis of anabasine in N. glauca. This aspect of the current study has been published recently (DeBoer et al., 2009)

Alkaloid Biology and Metabolism in Plants

Alkaloid Biology and Metabolism in Plants
Author: G. Waller
Publisher: Springer Science & Business Media
Total Pages: 302
Release: 2012-12-06
Genre: Science
ISBN: 1468407724

* This book is designed for the use of the advanced student and professional worker interested in the international scientific community, particularly those in the fields of agronomy, agricultural sciences, botany, biological sciences, natural products chemistry, pharmaceutical chemistry and bio chemistry. The purpose is to inform the reader about significant advances in the biology and metabolism of alkaloids in plants. Since alkaloids are generally referred to as "secondary metabolites," the reactions discussed are not, for the most part, involved with the main metabolic pathways. The reactions that we are interested in are pathways that have been developed for the formation of these secondary metabolites, using as their starting mole cules one of the compounds produced via a main or primary metabolic path way. The primary metabolic pathways are common to all plants, indeed to most living organisms, whereas the highly specialized branches leading to alkaloid formation are found in only about 10 to 20 % of the known plants. The reason for these diversities in plant metabolism is not clear; however, it seems likely that the formation of highly individualized and specialized pathways resulted as a response to the pressure of natural selection. Nevertheless, the genetic peculiarity that controls alkaloid production has provided many extremely interesting problems for scientists and consti tutes convincing evidence of nature's superior ability in biochemistry.

Biochemistry and Molecular Biology of Plants

Biochemistry and Molecular Biology of Plants
Author: Bob B. Buchanan
Publisher: John Wiley & Sons
Total Pages: 1280
Release: 2015-08-31
Genre: Science
ISBN: 0470714220

With over 1000 original drawings and 500 photographs, this work offers complete coverage of cell biology, plant physiology and molecular biology.

Tobacco BY-2 Cells

Tobacco BY-2 Cells
Author: Toshiyuki Nagata
Publisher: Springer Science & Business Media
Total Pages: 371
Release: 2013-03-09
Genre: Technology & Engineering
ISBN: 3662105721

The first compilation of a wealth of knowledge on tobacco BY-2 cells, often cited as the HeLa cell line of higher plants. Basic issues of cell cycle progression, cytokinesis, cell organization and factors that are involved in these processes are covered in detail. Since the tobacco cell line is used as a tool for research in molecular and cellular biology, several chapters on such studies are also included. Further, changes of primary and secondary metabolites during culture and factors that affect these processes are treated. Last but not least, the so far unpublished historical background of the BY-2 cell line is described. This volume is a must for any scientist working in the field of plant biology.

Medicinal, Aromatic and Stimulant Plants

Medicinal, Aromatic and Stimulant Plants
Author: Johannes Novak
Publisher: Springer
Total Pages: 0
Release: 2020-10-10
Genre: Science
ISBN: 9783030387914

The agricultural sector of medicinal (including plant stimulants) and aromatic plants is characterized by an enormous number and diversity of species. Only a few of them can be considered cultivated crops in which significant breeding efforts are made. For most species, however, breeding is performed in short-term projects only. Therefore, basic knowledge about these species is still fragmentary. Our intention is to compile and organize the available information on the most commonly utilized plant species into one publication, thereby providing a standardized resource for the researchers and the grower community. This book therefore provides reference source materials for a wide variety of plant species used for human consumption due to their flavor, medicinal or recreational properties. It is divided into a section of general topics on genetic resources, breeding adaptation of analytic methods and a compilation of basic data for DNA content, chromosome number and mating system followed by a section of 20 monographs on a species or species groups.

Plant Toxins

Plant Toxins
Author: P. Gopalakrishnakone
Publisher:
Total Pages:
Release:
Genre: Plant toxins
ISBN: 9789400767287

Alkaloid Synthesis

Alkaloid Synthesis
Author: Hans-Joachim Knoelker
Publisher: Springer Science & Business Media
Total Pages: 268
Release: 2012-01-13
Genre: Science
ISBN: 3642255280

Lycopodium Alkaloids: Isolation and Asymmetric Synthesis, by Mariko Kitajima and Hiromitsu Takayama.- Synthesis of Morphine Alkaloids and Derivatives, by Uwe Rinner and Tomas Hudlicky.- Indole Prenylation in Alkaloid Synthesis, by Thomas Lindel, Nils Marsch and Santosh Kumar Adla.- Marine Pyrroloiminoquinone Alkaloids, by Yasuyuki Kita and Hiromichi Fujioka.- Synthetic Studies on Amaryllidaceae and Other Terrestrially Derived Alkaloids, by Martin G. Banwell, Nadia Yuqian Gao, Brett D. Schwartz and Lorenzo V. White.- Synthesis of Pyrrole and Carbazole Alkaloids, by Ingmar Bauer and Hans-Joachim Knölker.-

Alkaloids

Alkaloids
Author: Margaret F. Roberts
Publisher: Springer Science & Business Media
Total Pages: 492
Release: 2013-04-17
Genre: Science
ISBN: 1475729057

Not since the late 1970s has a single work presented the biology of this heterogenous group of secondary alkaloids in such depth. Alkaloids, a unique treatise featuring leaders in the field, presents both the historical use of alkaloids and the latest discoveries in the biochemistry of alkaloid production in plants alkaloid ecology, including marine invertebrates, animal and plant parasites, and alkaloids as antimicrobial and current medicinal use . Highlights include chapters on the chemical ecology of alkaloids in host-predator interactions, and on the compartmentation of alkaloids synthesis, transport, and storage. Extensive cross-referencing in tabular format makes this volume an excellent reference.