title: Induced mutation in β-CAROTENE HYDROXYLASE results in accumulation of β-carotene and conversion of red to orange color in pepper fruit.
abstract: Pepper fruit is typically red, but green, orange and yellow cultivars are gaining consumer acceptance. This color variation is mainly due to variations in carotenoid composition. Orange color in pepper can result from a number of carotenoid profiles, but its genetic basis is only partly known. We identified an EMS-induced orange-fruited mutant using the wild-type blocky red-fruited cultivar 'Maor' as progenitor. This mutant accumulates mainly β-carotene in its fruit, instead of the complex pattern of red and yellow carotenoids in 'Maor'. We identified an A(709) to G transition in the cDNA of β-CAROTENE HYDROXYLASE2 in the orange pepper and complete co-segregation of this single-nucleotide polymorphism with the mutated phenotype. We therefore hypothesized that β-CAROTENE HYDROXYLASE2 controls the orange mutation in pepper. Interestingly, the expression of β-CAROTENE HYDROXYLASE2 and additional carotenogenesis genes was elevated in the orange fruit compared with the red fruit, indicating possible feedback regulation of genes in the pathway. Because carotenoids serve as precursors for volatile compounds, we compared the volatile profiles of the two parents. The orange pepper contained more volatile compounds than 'Maor', with predominant elevation of norisoprenoids derived from β-carotene degradation, while sesquiterpenes predominated in the red fruit. Because of the importance of β-carotene as a provitamin A precursor in the human diet, the orange-fruited mutant might serve as a natural source for pepper fruit biofortification. Moreover, the change in volatile profile may result in a fruit flavor that differs from other pepper cultivars.
authors.affiliation: Institute of Plant Sciences, The Volcani Center, Bet Dagan, Israel.
authors.forename: Yelena
authors.initials: Y
authors.lastname: Borovsky
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Tadmor
authors.forename: Einat
authors.initials: E
authors.lastname: Bar
authors.forename: Ayala
authors.initials: A
authors.lastname: Meir
authors.forename: Efraim
authors.initials: E
authors.lastname: Lewinsohn
authors.forename: Ilan
authors.initials: I
authors.lastname: Paran
mesh_terms: D002212:Capsicum / Q000737:chemistry / Q000201:enzymology / Q000235:genetics*; D005638:Fruit / Q000737:chemistry* / Q000201:enzymology; D008401:Gas Chromatography-Mass Spectrometry; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005819:Genetic Markers; D006899:Mixed Function Oxygenases / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D045792:Norisoprenoids / Q000032:analysis / Q000378:metabolism; D010641:Phenotype; D010858:Pigmentation; D017422:Sequence Analysis, DNA; D055549:Volatile Organic Compounds / Q000032:analysis; D019207:beta Carotene / Q000096:biosynthesis*
chemical_list: D005819:Genetic Markers; D045792:Norisoprenoids; D055549:Volatile Organic Compounds; D019207:beta Carotene; D006899:Mixed Function Oxygenases; C079232:beta-carotene hydroxylase