Evolution of pyrrolizidine alkaloids in Phalaenopsis orchids and other monocotyledons: identification of deoxyhypusine synthase, homospermidine synthase and related pseudogenes.
Phytochemistry
; 70(4): 508-16, 2009 Mar.
Article
en En
| MEDLINE
| ID: mdl-19254800
In order to study the evolution of pathways of plant secondary metabolism, we use the biosynthesis of pyrrolizidine alkaloids (PAs) as a model system. PAs are regarded as part of the plant's constitutive defense against herbivores. Homospermidine synthase (HSS) is the first specific enzyme of PA biosynthesis. The gene encoding HSS has been recruited from the gene encoding deoxyhypusine synthase (DHS) from primary metabolism at least four times independently during angiosperm evolution. One of these recruitment occurred within the monocot lineage. We have used the PA-producing orchid Phalaenopsis to identify the cDNAs encoding HSS, DHS and the substrate protein for DHS, i.e., the precursor of the eukaryotic initiation factor 5A. A cDNA identified from maize was unequivocally characterized as DHS. From our study of Phalaenopsis, several pseudogenes emerged, of which one was shown to be a "processed pseudogene", and others to be transcribed. Sequence comparison of the HSS- and DHS-encoding sequences from this investigation with those of monocot species taken from the databases suggest that HSS and probably the ability to produce PAs is an old feature within the monocot lineage. This result is discussed with respect to the recent discovery of structural related PAs within grasses.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Alcaloides de Pirrolicidina
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Seudogenes
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Evolución Molecular
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Transferasas Alquil y Aril
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Orchidaceae
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Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH
Tipo de estudio:
Diagnostic_studies
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Prognostic_studies
Idioma:
En
Revista:
Phytochemistry
Año:
2009
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Reino Unido