Control and biological implications of alkaloid synthesis inCinchona seedlings

Aerts, Rob J.; Snoeijer, Wim; Aerts-Teerlink, Olga; Meijden, E. van der; Verpoorte, Robert

doi:10.1016/0031-9422(91)80068-c

Cited by 32 publications

(19 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is particularly important in plants with a strategy "r" as L parasitica. The variation of the ergoline alkaloids during the very early development of L parasitica match with that reported by Aerts et al (1991) for Cinchona ledgeriana seedlings. Aerts and co-workers suggested that precursor pools for alkaloid synthesis in Cinchona are not exhausted at once because of the potential autotoxicity of the alkaloids; however, the alkaloid concentration present in the seedlings seems sufficient for ecological interaction at relatively low cost of carbon.…”

Section: Discussionsupporting

confidence: 81%

Allelochemical effects of ergoline alkaloids fromIpomoea parasitica onHeliothis virescens

Amor-Prats

Harborne

1993

Chemoecology

View full text Add to dashboard Cite

Abstract. Lysergol, elymoclavine and three other van Urk-positive alkaloids were identified by 2D chromatography in the seed extract of Ipomoea parasitica.The presence of the same ergoline alkaloids was also demonstrated in vegetative tissue of L parasitica. Heliothis virescens larvae reared on a diet containing an alkaloid extract of I. parasitica showed an increase in the consumption index and a reduction in the effiency of conversion of food. No difference was observed in the approximated digestibility. The percentages of pupation and emergence were reduced and the malefemale ratio was altered in insects fed on a diet containing the alkaloid extract of L parasitica or lysergol. The increases in the concentration of ergoline alkaloids in L parasitica at the seedling stage and at flowering support the theory that these compounds play a defensive role against herbivory in the plant.Key words, allelochemical effect -herbivory -chemical defence -ontogenetic variation -ergoline alkaloids -lysergol -elymoclavine -Ipomoea parasitica- Heliothis virescensIn spite of the considerable physiological activity of the ergoline alkaloids and of their use in pharmacology, little attention has been paid to their ecological role in the higher plants where they are present. However, some researchers have recently investigated the effect of ergoline alkaloids from endophyte (ergot)-infected grasses on certain arthropods. Yates et al. (1989) investigated the effect of ergoline alkaloids from endophyteinfected grasses on the milkweed bug Oncopeltus fasciatus. These authors found that a fraction containing simple lysergic acid amides, N-formylloline and related alkaloids was highly toxic while a fraction containing ergopeptine alkaloids proved to be relatively non-toxic, although commercial ergopeptines were toxic. Clay & Cheplick (1989) found that the ergoline alkaloids ergonovine, ergotamine, ergocryptine, agroclavine and elymoclavine but not lysergol reduce larval weight and/or leaf area consumption in the fall armyworm Spodoptera fugiperda.In this paper the possible ecological role of the ergoline alkaloids in L parasitica is discussed on the bases of their effect on H. virescens and their ontogenetic and organ variation.

show abstract

Section: Discussionsupporting

confidence: 81%

Allelochemical effects of ergoline alkaloids fromIpomoea parasitica onHeliothis virescens

Amor-Prats

Harborne

1993

Chemoecology

View full text Add to dashboard Cite

show abstract

“…This group of secondary metabolites is thought to have anti-herbivore activity and to function in protection against pathogens and/or UV radiation (Aerts et al 1991;Hartmann 1991;Luijendijk 1995;Thomas et al 1995). One of the key steps in the biosynthesis of terpenoid indole alkaloids is the condensation of the amino acid derivative tryptamine and the terpenoid secologanin, catalysed by the enzyme strictosidine synthase (EC 4.3.3.2.)…”

Section: Introductionmentioning

confidence: 99%

A G-box element from the Catharanthus roseus strictosidine synthase (Str) gene promoter confers seed-specific expression in transgenic tobacco plants

Ouwerkerk¹,

Memelink²

1999

Mol Gen Genet

View full text Add to dashboard Cite

The enzyme encoded by the strictosidine synthase (Str) gene from Catharanthus roseus catalyses a key step in the biosynthesis of the pharmaceutically important terpenoid indole alkaloids. Str cDNA and genomic clones have already been isolated, allowing us to study the regulation of Str gene expression. Here we focus on the role of a putative cis-acting element, CACGTG, in the Str promoter. This sequence is known as a G-box, and functions as a transcription-regulating sequence in a number of other promoters. By means of electrophoretic mobility shift assays it was demonstrated that the Str G-box is capable of interacting with nuclear factors in tobacco and with the cloned tobacco G-box-binding factor TAF-1. Disruption of the Str G-box sequence by two single-nucleotide mutations prevented binding of factors, thereby demonstrating the specificity of the observed interactions. Functional analysis in transgenic tobacco plants demonstrated that these mutations also reduced the transcriptional activity of constructs containing tetramers of the Str G-box sequence. Expression directed by a tetramer of the Str G-box fused to a truncated promoter containing only a TATA box was confined to seeds and was found to increase during seed maturation. Thus, the Str G-box tetramer is able to direct seed-specific expression independently of other regulatory sequences. G-box-directed expression in leaves required the presence of an enhancer region from the cauliflower mosaic virus (CaMV) 35S promoter. The results indicate that the G-box needs to interact with other elements to drive expression in leaf, and that it can by itself confer seed-specific expression as a multimer. The fact that only some of the G-boxes found in different promoters serve as seed-specific elements indicates that sequences flanking the G-box determine the transcriptional activity in different tissues. Based on sequence comparisons we propose that the nucleotides at positions -4, -3, -2 and/or +4 are important in determining seed-specific expression.

show abstract

“…It is thought that TIAs serve protective functions, like other classes of secondary metabolites such as other types of alkaloids (Hartmann 1991) or phenylpropanoid-derived phytoalexins (Dixon and Paiva 1995). Indeed, some experimental evidence suggests that TIAs are involved in defence by providing protection against microbial infection, herbivory or UV radiation (Aerts et al 1991;Luijendijk 1995;Thomas et al 1995). However, their exact role in the physiology of the plant remains to be elucidated.…”

Section: Introductionmentioning

confidence: 99%

Nuclear factors GT-1 and 3AF1 interact with multiple sequences within the promoter of the Tdc gene from Madagascar periwinkle: GT-1 is involved in UV light-induced expression

Ouwerkerk¹,

Trimborn²,

Hilliou³

et al. 1999

Mol Gen Genet

View full text Add to dashboard Cite

Plant secondary metabolites of the terpenoid indole alkaloid (TIA) class comprise several compounds with pharmaceutical applications. A key step in the TIA biosynthetic pathway is catalysed by the enzyme tryptophan decarboxylase (TDC), which channels the primary metabolite tryptophan into TIA metabolism. In Catharanthus roseus (Madagascar periwinkle), the Tdc gene is expressed throughout plant development. Moreover, Tdc gene expression is induced by external stress signals, such as fungal elicitor and UV light. In a previous study of Tdc promoter architecture in transgenic tobacco it was shown that the -538 to -112 region is a quantitative determinant for the expression level in different plant organs. Within this sequence one particular region (-160 to -99) was identified as the major contributor to basal expression and another region (-99 to -37) was shown to be required for induction by fungal elicitor. Here, the in vitro binding of nuclear factors to the -572 to -37 region is described. In extracts from tobacco and C. roseus, two binding activities were detected that could be identified as the previously described nuclear factors GT-1 and 3AF1, based on their mobility and binding characteristics. Both factors appeared to interact with multiple regions in the Tdc promoter. Mutagenesis of GT-1 binding sites in the Tdc promoter did not affect the basal or elicitor-induced expression levels. However, induction of the Tdc promoter constructs by UV light was significantly lower, thereby demonstrating a functional role for GT-1 in the induction of Tdc expression by UV light.

show abstract

Control and biological implications of alkaloid synthesis inCinchona seedlings

Cited by 32 publications

References 20 publications

Allelochemical effects of ergoline alkaloids fromIpomoea parasitica onHeliothis virescens

Allelochemical effects of ergoline alkaloids fromIpomoea parasitica onHeliothis virescens

A G-box element from the Catharanthus roseus strictosidine synthase (Str) gene promoter confers seed-specific expression in transgenic tobacco plants

Nuclear factors GT-1 and 3AF1 interact with multiple sequences within the promoter of the Tdc gene from Madagascar periwinkle: GT-1 is involved in UV light-induced expression

Contact Info

Product

Resources

About