scholarly journals Pyrrolizidine Alkaloid Biosynthesis in Phalaenopsis Orchids: Developmental Expression of Alkaloid-Specific Homospermidine Synthase in Root Tips and Young Flower Buds

2008 ◽  
Vol 148 (2) ◽  
pp. 751-760 ◽  
Author(s):  
Sven Anke ◽  
Daniela Gondé ◽  
Elisabeth Kaltenegger ◽  
Robert Hänsch ◽  
Claudine Theuring ◽  
...  
Keyword(s):  
Pyrrolizidine Alkaloid ◽  
Developmental Expression ◽  
Alkaloid Biosynthesis ◽  
Root Tips ◽  
Flower Buds ◽  
Homospermidine Synthase

scholarly journals The Orphan Crop Crassocephalum crepidioides Accumulates the Pyrrolizidine Alkaloid Jacobine in Response to Nitrogen Starvation

2021 ◽  
Vol 12 ◽  
Author(s):  
Sebastian Schramm ◽  
Wilfried Rozhon ◽  
Adebimpe N. Adedeji-Badmus ◽  
Yuanyuan Liang ◽  
Shahran Nayem ◽  
...  
Keyword(s):  
Pyrrolizidine Alkaloid ◽  
Sub Saharan Africa ◽  
Close Relative ◽  
Environmental Cues ◽  
N Deficiency ◽  
Sub Saharan ◽  
Rate Limiting ◽  
Homospermidine Synthase ◽  
Orphan Crop

Crassocephalum crepidioides is an African orphan crop that is used as a leafy vegetable and medicinal plant. Although it is of high regional importance in Sub-Saharan Africa, the plant is still mainly collected from the wild and therefore efforts are made to promote its domestication. However, in addition to beneficial properties, there was first evidence that C. crepidioides can accumulate the highly toxic pyrrolizidine alkaloid (PA) jacobine and here it was investigated, how jacobine production is controlled. Using ecotypes from Africa and Asia that were characterized in terms of their PA profiles, it is shown that the tetraploid C. crepidioides forms jacobine, an ability that its diploid close relative Crassocephalum rubens appears to lack. Evidence is provided that nitrogen (N) deficiency strongly increases jacobine in the leaves of C. crepidioides, that this capacity depends more strongly on the shoot than the root system, and that homospermidine synthase (HSS) activity is not rate-limiting for this reaction. A characterization of HSS gene representation and transcription showed that C. crepidioides and C. rubens possess two functional versions, one of which is conserved, that the HSS transcript is mainly present in roots and that its abundance is not controlled by N deficiency. In summary, this work improves our understanding of how environmental cues impact PA biosynthesis in plants and provides a basis for the development of PA-free C. crepidioides cultivars, which will aid its domestication and safe use.

scholarly journals Identification of a Second Site of Pyrrolizidine Alkaloid Biosynthesis in Comfrey to Boost Plant Defense in Floral Stage,

2017 ◽  
Vol 174 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Lars H. Kruse ◽  
Thomas Stegemann ◽  
Christian Sievert ◽  
Dietrich Ober
Keyword(s):  
Plant Defense ◽  
Pyrrolizidine Alkaloid ◽  
Alkaloid Biosynthesis

scholarly journals Mitotic and meiotic studies on two species of Ocimum (Lamiaceae) and their F1 hybrids

2017 ◽  
Vol 23 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Johnson Ademola Idowu ◽  
Matthew Oziegbe
Keyword(s):  
Chromosome Number ◽  
Chromosome Numbers ◽  
Interspecific Variation ◽  
F1 Hybrids ◽  
Root Tips ◽  
Flower Buds ◽  
Ploidy Levels ◽  
Ocimum Species ◽  
Karyotype Formula ◽  
Standard Techniques

AbstractOcimum L. species are important aromatic and medicinal plants. Many researchers have observed complexity in their chromosome numbers and ploidy levels. We studied the somatic and germline chromosomal features and behaviour of Ocimum basilicum L., two variants of O. canum Sims (‘c1’ and ‘c2’) and their F1hybrids. Chromosomes from root tips and flower buds were investigated using standard techniques; karyograms were formed and analysed. A chromosome number of 2n = 4x = 52 was observed in O. basilicum and O. canum ‘c1’ and their F1hybrid. One of the variants, O. canum ‘c2’ had a chromosome number of 2n = 2x = 24 and its intraspecific hybrid O. canum ‘c2’ × O. canum ‘c1’ had a chromosome number of 2n = 38. These Ocimum species and their F1hybrids showed different karyotype formula, but their chromosomes were mostly metacentric (174) and submetacentric (36) with few subtelocentric (8). Based on pairing configuration, O. basilicum is an allotetraploid plant, O. canum ‘c1’ is an autotetraploid plant and the O. canum ‘c1’ is a diploid. The F1 hybrids showed higher frequency of meiotic abnormalities than the parents. The study showed intraspecific and interspecific variation in chromosome numbers and pairing patterns, but the chromosomes of the Ocimum species were similar in their centromeric positions.

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