AOBPreview published online on June 27, 2008
Annals of Botany, doi:10.1093/aob/mcn108
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Vindoline Formation in Shoot Cultures of Catharanthus roseus is Synchronously Activated with Morphogenesis Through the Last Biosynthetic Step
Unidad de Bioquímica y Biología Molecular de Plantas and Graduate Program in Plant Sciences and Biotechnology, Centro de Investigación Científica de Yucatán, Calle 43 No. 130 Chuburná, Mérida Yucatán 97200, México
* For correspondence. E-mail felipe{at}cicy.mx
Received: 6 March 2008 Returned for revision: 8 May 2008 Accepted: 4 June 2008
Background and Aims: The Madagascar periwinkle (Catharanthus roseus) produces the monoterpenoid alkaloid vindoline, which requires a specialized cell organization present only in the aerial tissues. Vindoline content can be affected by photoperiod and this effect seems to be associated with the morphogenetic capacity of branches; this association formed the basis of the study reported here.
Methods: Vindoline-producing in vitro shoot cultures were exposed either to continuous light or a 16-h photoperiod regime. New plantlet formation and alkaloid biosynthesis were analysed throughout a culture cycle.
Key Results: In cultures under the photoperiod, the formation of new plantlets occurred in a more synchronized fashion as compared to those under continuous light. The accumulation of vindoline in cultures under the photoperiod occurred in co-ordination with plantlet formation, in constrast to cultures under continuous light, and coincided with a peak of activity of deacetylvindoline acetyl CoA acetyltransferase (DAT), the enzyme that catalyses the last step in vindoline biosynthesis. When new plantlet formation was blocked in cultures under the photoperiod by treatment with phytoregulators, vindoline synthesis was also reduced via an effect on DAT activity. No association between plantlet formation and other biosynthetic enzymes, such as tryptophan decarboxylase (TDC) and deacetoxyvindoline 4-hydroxylase (D4H), was found. Effects of light treatment on vindoline synthesis were not mediated by ORCA-3 proteins (which are involved in the induction of alkaloid synthesis in response to elicitation), suggesting that the presence of a different set of regulatory proteins.
Conclusions: The data suggest that vindoline biosynthesis is associated with morphogenesis in shoot cultures of C. roseus.
Key words: Catharanthus roseus, deacetylvindoline acetyl CoA acetyltransferase, DAT, in vitro shoot cultures, morphogenesis, vindoline
Present address: Hospital General Agustín O'Horán, Calle 59 A S/N Mérida Yucatán 97000, México.
Present address: Unidad de Investigación en Biotecnología Vegetal, Instituto Tecnológico Superior de Acayucán, Carretera Costera del Golfo Km. 216·4 Col. Agrícola Michapa, Acayucán Veracruz 96100, México