The Experts below are selected from a list of 3039 Experts worldwide ranked by ideXlab platform
Lourdes Gomezgomez - One of the best experts on this subject based on the ideXlab platform.
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the expression of a chromoplast specific Lycopene beta cyclase gene is involved in the high production of saffron s apocarotenoid precursors
Journal of Experimental Botany, 2010Co-Authors: Oussama Ahrazem, Angela Rubiomoraga, Raquel Castillo Lopez, Lourdes GomezgomezAbstract:Crocus sativus is a triploid sterile plant characterized by its long red stigmas, which produce and store significant quantities of carotenoid derivatives formed from the oxidative cleavage of b-carotene and zeaxanthin. The present study reports on the genomic structures of two Lycopene-b-cyclase genes, CstLcyB1 and CstLcyB2a, and on their transcription patterns in different C. sativus tissues. Phylogenetic analysis showed that both proteins are located in different groups: CstLcyB2a encodes chromoplast-specific Lycopene cyclases, with an expression analysis showing strongly in flower stigmas where it activates and boosts b-carotene accumulation. The CstLcyB1 transcript, however, was present in leaves, tepals, and stigmas at lower levels. In vivo assays in transgenic Arabidopsis demonstrated Lycopene b-cyclase activity of CstLcyB2a. CstLcyB2a is a CstLcyB1 paralogue derived through a gene duplication event, while promoter analysis showed that both genes have diverged in their regulatory sequences after duplication. Furthermore, it was found that the CstLcyB2a gene was absent from Crocus kotschyanus and, although present in C. goulimyi and C. cancellatus, the absence of transcripts suggests that transcriptional regulation of CstLcyB2a is responsible for the low apocarotenoid content in these species.
Renata Riveramadrid - One of the best experts on this subject based on the ideXlab platform.
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functional polymorphism in Lycopene beta cyclase gene as a molecular marker to predict bixin production in bixa orellana l achiote
Molecular Breeding, 2016Co-Authors: Jose Abraham Trujillohdz, Yair Cardenasconejo, Pedro Escobar Turriza, Margarita Aguilarespinosa, Victor Manuel Carballouicab, Luz Elena Garzacaligaris, Luca Comai, Renata RiveramadridAbstract:Bixin is an apocarotenoid obtained from the seed aril of Bixa orellana L., a tropical plant known as achiote in Mexico. This compound is the second most commonly used natural colouring for food and pharmaceutical industries. B. orellana is an outcrossing species that displays high genetic variability. Recently, the colour traits of sexual organs were associated with the biosynthesis and accumulation of bixin in mature seeds. Herein, we describe a new approach for genotype–phenotype association by surveying Lycopene Beta-Cyclase (Boβ-LCY1) gene variation in sixteen achiote accessions divided into three groups according to contrasting traits, such as flower colour, fruit colour and bixin production. Using a combination of single-strand conformational polymorphism techniques and the sequencing of polymorphic bands, we identified several single-nucleotide polymorphisms that divided the accessions into three haplotypes. Surprisingly, we observed that these three haplotypes were consistent with the same three groups previously characterized by phenotypic traits. We derived a putative sequence for the Boβ-LCY1 gene and surveyed the variations in this sequence. The heterozygosity of Boβ-LCY1 alleles resulted in a higher bixin content, likely associated with heterosis for this metabolite. These findings augment the toolbox available for the selection and genetic improvement of B. orellana and provide a reliable phenotype–genotype association method for commercial varietal selection, contributing to the development of laboratory techniques to identify desirable traits of commercial plant species.
Rameshwar Sharma - One of the best experts on this subject based on the ideXlab platform.
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neofunctionalization of chromoplast specific Lycopene beta cyclase gene cyc b in tomato clade
PLOS ONE, 2016Co-Authors: Vijee Mohan, Arun Kumar Pandey, Yellamaraju Sreelakshmi, Rameshwar SharmaAbstract:The ancestor of tomato underwent whole genome triplication ca. 71 Myr ago followed by widespread gene loss. However, few of the triplicated genes are retained in modern day tomato including Lycopene beta cyclase that mediates conversion of Lycopene to β-carotene. The fruit specific β-carotene formation is mediated by a chromoplast-specific paralog of Lycopene beta cyclase (CYC-B) gene. Presently limited information is available about how the variations in CYC-B gene contributed to its neofunctionalization. CYC-B gene in tomato clade contained several SNPs and In-Dels in the coding sequence (33 haplotypes) and promoter region (44 haplotypes). The CYC-B gene coding sequence in tomato appeared to undergo purifying selection. The transit peptide sequence of CYC-B protein was predicted to have a stronger plastid targeting signal than its chloroplast specific paralog indicating a possible neofunctionalization. In promoter of two Bog (Beta old gold) mutants, a NUPT (nuclear plastid) DNA fragment of 256 bp, likely derived from a S. chilense accession, was present. In transient expression assay, this promoter was more efficient than the “Beta type” promoter. CARGATCONSENSUS box sequences are required for the binding of the MADS-box regulatory protein RIPENING INHIBITOR (RIN). The loss of CARGATCONSENSUS box sequence from CYC-B promoter in tomato may be related to attenuation of its efficiency to promote higher accumulation of β-carotene than Lycopene during fruit ripening.
Oussama Ahrazem - One of the best experts on this subject based on the ideXlab platform.
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the expression of a chromoplast specific Lycopene beta cyclase gene is involved in the high production of saffron s apocarotenoid precursors
Journal of Experimental Botany, 2010Co-Authors: Oussama Ahrazem, Angela Rubiomoraga, Raquel Castillo Lopez, Lourdes GomezgomezAbstract:Crocus sativus is a triploid sterile plant characterized by its long red stigmas, which produce and store significant quantities of carotenoid derivatives formed from the oxidative cleavage of b-carotene and zeaxanthin. The present study reports on the genomic structures of two Lycopene-b-cyclase genes, CstLcyB1 and CstLcyB2a, and on their transcription patterns in different C. sativus tissues. Phylogenetic analysis showed that both proteins are located in different groups: CstLcyB2a encodes chromoplast-specific Lycopene cyclases, with an expression analysis showing strongly in flower stigmas where it activates and boosts b-carotene accumulation. The CstLcyB1 transcript, however, was present in leaves, tepals, and stigmas at lower levels. In vivo assays in transgenic Arabidopsis demonstrated Lycopene b-cyclase activity of CstLcyB2a. CstLcyB2a is a CstLcyB1 paralogue derived through a gene duplication event, while promoter analysis showed that both genes have diverged in their regulatory sequences after duplication. Furthermore, it was found that the CstLcyB2a gene was absent from Crocus kotschyanus and, although present in C. goulimyi and C. cancellatus, the absence of transcripts suggests that transcriptional regulation of CstLcyB2a is responsible for the low apocarotenoid content in these species.
Maria Jesus Rodrigo - One of the best experts on this subject based on the ideXlab platform.
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molecular and functional characterization of a novel chromoplast specific Lycopene β cyclase from citrus and its relation to Lycopene accumulation
Journal of Experimental Botany, 2009Co-Authors: Berta Alquezar, Lorenzo Zacarias, Maria Jesus RodrigoAbstract: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.
