The Strange Fate of Pyrrolizidine Alkaloids

Schneider, Dietrich

doi:10.1007/978-1-4612-4644-2_8

Cited by 41 publications

(11 citation statements)

References 50 publications

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“…If, however, one adopts a heuristic view of evolution, then there is not necessarily a need for a plant to degrade or turn over a secondary compound selected as a constitutive defence chemical, a function generally accepted for pyrrolizidine alkaloids [16,17]. To fulfil this ecochemical function, the newly synthesized alkaloid molecules need only be translocated and channelled to the specific sites of storage, i.e.…”

Section: Discussionmentioning

confidence: 99%

Site of synthesis, metabolism and translocation of senecionine N-oxide in cultured roots of Senecio erucifolius

Sander

Hartmann

1989

Plant Cell Tiss Organ Cult

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Root cultures of Senecio erucifolius (Asteraceae) efficiently took up and incorporated [~4C]putrescine and [~4C]arginine into the pyrrolizidine alkaloid (PA) senecionine N-oxide. Pulse-chase experiments covering a growth period of 10 to 19 days revealed the absence of any significant alkaloid turnover. The only metabolic activity was a slow but progressive transformation of senecionine N-oxide into its dehydrogenation product, seneciphylline N-oxide. Tracer experiments with single roots showed that the sites of enhanced PA synthesis coincided with the sites of preferred protein synthesis, i.e. root apices, indicating a close correlation between growth activity and alkaloid synthesis. Long-term pulse-chase experiments (10 to 12 days) with ~4C-labelled arginine, putrescine and senecionine fed to single roots indicated that in spite of its metabolic inertia, senecionine N-oxide is a mobile compound which is translocated into tissues newly grown during the chase.

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Section: Discussionmentioning

confidence: 99%

Site of synthesis, metabolism and translocation of senecionine N-oxide in cultured roots of Senecio erucifolius

Sander

Hartmann

1989

Plant Cell Tiss Organ Cult

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“…The PAs are regarded as powerful defence compounds, particularly against herbivorous insects (for review, see BoppreÁ 1986;Schneider 1987;Hartmann 1991;Hartmann and Witte 1995). They are unique among plant alkaloids in respect of their attractiveness to specialized insects.…”

Section: Introductionmentioning

confidence: 99%

Chemical diversity and variation of pyrrolizidine alkaloids of the senecionine type: biological need or coincidence?

Hartmann

Dierich

1998

Planta

127

104

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Laboratory and ®eld tracer experiments with 14 C-labelled senecionine N±oxide (SO) and distant biosynthetic precursors such as [ 14 C]putrescine revealed that pyrrolizidine alkaloid N-oxides (PAs) in Senecio vernalis Waldstr. & Kit. (Asteraceae) show no signi®cant turnover over periods of up to 29 d. However, PAs are spatially mobile, they are continuously allocated, and labelled PAs are even detectable in leaves and capitula developed weeks after tracer application. Chemical diversi®cation of SO, the common product of PA biosynthesis in roots, was studied in ®ve Senecio species (i.e. S. vernalis Waldstr. & Kit., S. vulgaris L, S. inaequidens DC, two chemotypes of S. jacobaea L. and S. erucifolius L.). Tracer experiments revealed that shoots are capable of transforming [ 14 C]SO into the unique species±speci®c PA patterns. Within a plant, the transformation eciency of SO can vary quantitatively and qualitatively between shoot organs (i.e. leaves, stems and in¯orescences). All transformations proceed position-speci®cally and stereoselectively. They comprise simple one-step or two-step reactions such as hydroxylations, epoxidations, dehydrogenations, and O-acetylations, as well as the more complex conversion of the retronecine into the otonecine base moiety (e.g. SO into senkirkine). Taking all the evidence together, the qualitative and quantitative composition of the Senecio PA pattern is a dynamic and sensitive equilibrium between a number of interacting processes: (i) constant rate of de-novo synthesis of SO in roots, (ii) continuous longdistance translocation of SO into shoots, (iii) eciency of SO transformations which may vary between plant organs, (iv) continuous allocation of PAs in the plant, and (v) eciency and tissue selectivity of vacuolar storage. We suggest that in constitutive plant defence, without signi®cant turnover of its components, such a highly plastic system provides a powerful strategy to successfully defend and possibly escape herbivory.

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“…PAs are known as chemical defense compounds served as deterrent or toxic to herbivores and pathogens (Boppré 1986;Schneider 1987;Macel 2003;Molyneux et al, 2011). They play a role in plant resistance to most vertebrates and generalist herbivores (Schneider 1987;Macel 2003;Cheng et al, 2011b) and pathogens (Hol & Van Veen 2002;Singh et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…They play a role in plant resistance to most vertebrates and generalist herbivores (Schneider 1987;Macel 2003;Cheng et al, 2011b) and pathogens (Hol & Van Veen 2002;Singh et al, 2002). PAs functioned in the resistance against generalist herbivores (Leiss et al, 2009b;Macel & Klinkhamer 2010) such as generalist snail (Helix aspersa) (Cano et al, 2009), leafminer (Liriomyzia moth), western flower thrips (Franklinella occidentalis) (Cheng 2012), Brachycaudus cardii (Vrieling et al, 1990;Macel 2003;Leiss et al, 2009a).…”

Section: Introductionmentioning

confidence: 99%

Variation of pyrrolizidine alkaloids in Senecio vulgaris plants from native and invasive ranges

Cheng

Nguyen

Ndihokubwayo

et al. 2016

Preprint

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Pyrrolizidine alkaloids (PAs), a typical kind of secondary metabolites in plants, have important roles on defense against herbivores and pathogens; however, specialist herbivores adapted to PAs can use them as cues for oviposition and feeding. Thus, in the native ranges, PA diversity and concentration in plants were selected by the balance between pressure from generalist and specialist herbivores. In introduced ranges, where the specialist herbivores are absent, the introduced plants could increase concentration and diversity of PAs. This predication is deduced from the Shift Defense Hypothesis (SDH). In this research, we investigated whether there were any differences between native and invasive Senecio vulgaris plants (from Europe and China, respectively) with regards to the PA composition and concentration. We grew the native and invasive S. vulgaris plants in an identical condition and harvested them when they started to bloom. Their roots and shoots were separately harvested and dried. PA composition and concentration from powder of the shoots and roots were detected by using liquid chromatography -tanderm mass spectrometry (LC-MS/MS). We identified 14 PAs which belongs to the structural group senecionine -like PAs. Most of them occurred in both the native and invasive S. vulgaris plants, except the usaramine N -oxide that was only found in the native ones. From the 14 PAs identified, only riddelliine N -oxide had significantly higher present frequency in the invasive plants than in the native plants. The invasive S. vulgaris plants had significantly lower concentration of 3 individual PAs (seneciphylline N -oxide, spartioidine and spartioidine N -oxide) than the native ones. These results demonstrated that PA diversity and concentration of some individual PAs tended to reduce in the invasive range of S. vulgaris. This is contrary to the predictions of the SDH that the invasive plants would produce more qualitative defense than the native ones, and it is probably an evidence that a little trade -off between defense and growth happened to the S. vulgaris in China.

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The Strange Fate of Pyrrolizidine Alkaloids

Cited by 41 publications

References 50 publications

Site of synthesis, metabolism and translocation of senecionine N-oxide in cultured roots of Senecio erucifolius

Site of synthesis, metabolism and translocation of senecionine N-oxide in cultured roots of Senecio erucifolius

Chemical diversity and variation of pyrrolizidine alkaloids of the senecionine type: biological need or coincidence?

Variation of pyrrolizidine alkaloids in Senecio vulgaris plants from native and invasive ranges

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