Unknown

Dataset Information

0

Molecular and functional characterization of a novel chromoplast-specific lycopene beta-cyclase from Citrus and its relation to lycopene accumulation.


ABSTRACT: Carotenoids are the main pigments responsible of the colouration of Citrus fruits. The beta-cyclization of lycopene, catalysed by the lycopene beta-cyclases (beta-LCY), seems to be a key regulatory step of the carotenoid pathway. In the present study, two beta-LCYs from orange fruits (Citrus sinensis), named Csbeta-LCY1 and Csbeta-LCY2 have been isolated and the activity of the encoded proteins was demonstrated by functional analysis. Csbeta-LCY1 was expressed at low levels and remained relatively constant during fruit ripening while Csbeta-LCY2 showed a chromoplast-specific expression and a marked induction in both peel and pulp of orange fruits in parallel with the accumulation of beta,beta-xanthophylls. The potential involvement of Csbeta-LCY2 in the accumulation of lycopene, characteristic of some Citrus species such as red grapefruits, was investigated. Expression of Csbeta-LCY2 and another seven carotenoid biosynthetic genes were studied in the peel and pulp of the high lycopene-accumulating grapefruit, Star Ruby, and compared with those of ordinary Navel orange. In Star Ruby, the accumulation of lycopene during fruit maturation was associated with a substantial reduction in the expression of both beta-LCY2 and beta-CHX genes with respect to Navel orange. Moreover, two different alleles of beta-LCY2: beta-LCY2a and beta-LCY2b were isolated from both genotypes, and functional assays demonstrated that the lycopene beta-cyclase activity of the allele b was almost null. Interestingly, Star Ruby grapefruit predominantly expressed the unfunctional beta-LCY2b allele during fruit ripening whereas Navel oranges preferably expressed the functional allele. It is suggested that the presence of diverse alleles of the beta-LCY2 gene, encoding enzymes with altered activity, with different transcript accumulation may be an additional regulatory mechanism of carotenoid synthesis involved in the accumulation of lycopene in red grapefruits.

SUBMITTER: Alquezar B 

PROVIDER: S-EPMC2671624 | biostudies-literature | 2009

REPOSITORIES: biostudies-literature

altmetric image

Publications

Molecular and functional characterization of a novel chromoplast-specific lycopene beta-cyclase from Citrus and its relation to lycopene accumulation.

Alquézar Berta B   Zacarías Lorenzo L   Rodrigo María J MJ  

Journal of experimental botany 20090326 6


Carotenoids are the main pigments responsible of the colouration of Citrus fruits. The beta-cyclization of lycopene, catalysed by the lycopene beta-cyclases (beta-LCY), seems to be a key regulatory step of the carotenoid pathway. In the present study, two beta-LCYs from orange fruits (Citrus sinensis), named Csbeta-LCY1 and Csbeta-LCY2 have been isolated and the activity of the encoded proteins was demonstrated by functional analysis. Csbeta-LCY1 was expressed at low levels and remained relative  ...[more]

Similar Datasets

| S-EPMC4829152 | biostudies-literature
| S-EPMC5020073 | biostudies-literature
| S-EPMC6995616 | biostudies-literature
| S-EPMC2923535 | biostudies-literature
| S-EPMC2736891 | biostudies-literature
| S-EPMC2791114 | biostudies-literature
| S-EPMC5408262 | biostudies-literature
| S-EPMC3286453 | biostudies-literature
| S-EPMC3612080 | biostudies-literature
| S-EPMC8882798 | biostudies-literature