Molecular cloning of an aldehyde dehydrogenase implicated in artemisinin biosynthesis in Artemisia annuaThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 635-642 ◽  
Author(s):  
Keat H. Teoh ◽  
Devin R. Polichuk ◽  
Darwin W. Reed ◽  
Patrick S. Covello

Limitations in the supply of the antimalarial compound artemisinin from Artemisia annua  L. have led to an interest in understanding its biosynthesis and enhancing its production. Recent biochemical and molecular genetic data have implicated dihydroartemisinic aldehyde as a precursor to the corresponding acid, which is then converted to artemisinin. Thus, it is important to understand the enzyme or enzymes involved in dihydroartemisinic aldehyde oxidation. Given its activity on artemisinic aldehyde, the cytochrome P450 CYP71AV1 was investigated for its ability to oxidize dihydroartemisinic aldehyde. However, no net activity was detected. In a search for alternative enzymes that could catalyze the oxidation, an expressed sequence tag (EST) collection from A. annua was investigated for relevant cDNAs. This led to the isolation of a full-length cDNA encoding an aldehyde dehydrogenase homologue, named Aldh1, which is highly expressed in trichomes. Expression of the cDNA in E. coli and characterization of the purified recombinant enzyme revealed that the gene product catalyses the NAD(P)-dependent oxidation of the putative artemisinin precursors, artemisinic and dihydroartemsinic aldehydes, and a limited range of other aldehydes. The observed enzyme activity of Aldh1 and the expression pattern of the corresponding gene suggest a role in artemisinin biosynthesis in the glandular secretory trichomes of A. annua.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 643-649 ◽  
Author(s):  
Yansheng Zhang ◽  
Keat H. Teoh ◽  
Darwin W. Reed ◽  
Patrick S. Covello

The molecular genetics of carbon–carbon double bond reduction in the plant Artemisia annua  L. was studied. Expressed sequence tags from this plant were investigated for sequences with similarity to known double-bond reductases. This resulted in the isolation of a cDNA, corresponding to the gene A. annua Dbr1 (Double bond reductase1), encoding a member of the medium chain dehydrogenase/reductase protein superfamily with sequence similarity to tobacco allyl alcohol dehydrogenase. Recombinant A. annua Dbr1 protein was purified from Escherischia coli and shown to catalyze the reduction of the carbon–carbon double bond of 2-alkenals. This activity included the reduction of the double bond at C11–C13 in the artemisinin precursor artemisinic aldehyde, albeit with unnatural stereochemistry. The substrate specificity, product stereochemistry, and expression pattern of A. annua Dbr1 point to its involvement in planta in the detoxification of 2-alkenals, which may be generated under oxidative stress conditions.


Planta Medica ◽  
2011 ◽  
Vol 77 (12) ◽  
Author(s):  
O Kayser ◽  
A Ryden ◽  
H Bouwmeester ◽  
C Ruyter Spira ◽  
H Osada ◽  
...  

2020 ◽  
Vol 36 (3) ◽  
pp. 34-45
Author(s):  
T.Yu. Mitiuchkina ◽  
A.S. Pushin ◽  
A.K. Tzareva ◽  
A.M. Vainstein ◽  
S.V. Dolgov

Artemisinin-based medicines are the most effective treatment for malaria. To date, the wormwood plants (Artemisia annua L.) are the main source of artemisinin. Due to the limited nature of this source, considerable efforts are directed towards the development of methods for artemisinin production via heterologous expression systems. We used in this study agrobacterial transformation to transfer the genetic module of the artemisinin biosynthesis pathway into plants and then analyzed its transcription in a heterologous host. Tobacco plants were transformed with the artemisinin biosynthesis genes encoding amorpha-4,11-diene synthase, artemisin-aldehyde All(13) reductase, amorpha-4,11-diene monooxygenase, cytochrome P450 reductase from A. annua and yeast 3-hydroxy-3-methylglutaryl-coenzyme A reductase cloned in the pArtemC vector; farnesyl diphosphate synthase and aldehyde dehydrogenase were used to transform the plants as parts of vector p2356. As a result of transformation with the pArtemC and p2356 vectors, in twos transgenic lines with all target genes were obtained. Five genes of artemisinin biosynthesis and two genes of biosynthesis of its precursors were successfully transferred into the genome of transgenic tobacco lines as a result of the co-transformation with abovementioned vectors. Thus, the entire artemisinin biosynthesis pathway was first reconstructed in heterologous plants: the transcription of the artemisinin biosynthesis genes in the tobacco plants was shown via RT-PCR. The obtained results will be used in further research on expression systems for the production of artemisinin and other non-protein substances in heterologous host plants. artemisinin, malaria, metabolic engineering, tobacco, transgenic plants This work was supported by a Grant from the Russian Science Foundation no. 19-14-00190.


Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 58
Author(s):  
Patharajan Subban ◽  
Yaarit Kutsher ◽  
Dalia Evenor ◽  
Eduard Belausov ◽  
Hanita Zemach ◽  
...  

Shoot regeneration is a key tool of modern plant biotechnology. While many researchers use this process empirically, very little is known about the early molecular genetic factors and signaling events that lead to shoot regeneration. Using tobacco as a model system, we found that the inductive events required for shoot regeneration occur in the first 4–5 days following incubation on regeneration medium. Leaf segments placed on regeneration medium did not produce shoots if removed from the medium before four days indicating this time frame is crucial for the induction of shoot regeneration. Leaf segments placed on regeneration medium for longer than five days maintain the capacity to produce shoots when removed from the regeneration medium. Analysis of gene expression during the early days of incubation on regeneration medium revealed many changes occurring with no single expression pattern evident among major gene families previously implicated in developmental processes. For example, expression of Knotted gene family members increased during the induction period, whereas transcription factors from the Wuschel gene family were unaltered during shoot induction. Expression levels of genes involved in cell cycle regulation increased steadily on regeneration medium while expression of NAC genes varied. No obvious possible candidate genes or developmental processes could be identified as a target for the early events (first few days) in the induction of shoot regeneration. On the other hand, observations during the early stages of regeneration pointed out that regeneration does not occur from a single cell but a group of cells. We observed that while cell division starts just as leaf segments are placed on regeneration medium, only a group of cells could become shoot primordia. Still, these primordia are not identifiable during the first days.


2009 ◽  
Vol 70 (9) ◽  
pp. 1123-1128 ◽  
Author(s):  
Mikael E. Olsson ◽  
Linda M. Olofsson ◽  
Ann-Louise Lindahl ◽  
Anneli Lundgren ◽  
Maria Brodelius ◽  
...  

2015 ◽  
Vol 370 (1660) ◽  
pp. 20130378 ◽  
Author(s):  
Yinqiu Cui ◽  
Li Song ◽  
Dong Wei ◽  
Yuhong Pang ◽  
Ning Wang ◽  
...  

The Yuan Dynasty (AD 1271–1368) was the first dynasty in Chinese history where a minority ethnic group (Mongols) ruled. Few cemeteries containing Mongolian nobles have been found owing to their tradition of keeping burial grounds secret and their lack of historical records. Archaeological excavations at the Shuzhuanglou site in the Hebei province of China led to the discovery of 13 skeletons in six separate tombs. The style of the artefacts and burials indicate the cemetery occupants were Mongol nobles. However, the origin, relationships and status of the chief occupant (M1m) are unclear. To shed light on the identity of the principal occupant and resolve the kin relationships between individuals, a multidisciplinary approach was adopted, combining archaeological information, stable isotope data and molecular genetic data. Analysis of autosomal, mitochondrial and Y-chromosomal DNA show that some of the occupants were related. The available evidence strongly suggests that the principal occupant may have been the Mongol noble Korguz. Our study demonstrates the power of a multidisciplinary approach in elucidating information about the inhabitants of ancient historical sites.


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