Mutation Associated with Orange Fruit Color Increases Concentrations of β-Carotene in a Sweet Pepper Variety (Capsicum annuum L.)

Abstract

Pepper is the second most important vegetable crop in Bulgarian agriculture and has become the subject of extensive breeding programs that frequently employ induced mutagenesis. The success of breeding programs can be enhanced by the efficient and integral application of different biochemical and molecular methods to characterize specific mutant alleles. On the other hand, identifying new cost-effective methods is important under a limited-resources environment. In this paper we compare the levels of five health-related carotenoid compounds of fruits (α-carotene, β-carotene, lutein, β-cryptoxanthin, zeaxanthin) between a mutant variety Oranzheva kapia (possessing high ß-carotene concentration) and a corresponding initial pepper variety Pazardzhishka kapia 794. Both varieties are intended for fresh consumption. Pepper is a major natural source of β-carotene. It was observed that fruit at both commercial and botanical maturity from mutant variety had greater α-carotene and β-carotene concentrations to the initial variety (7.49 and 1.94 times higher, respectively) meaning that the mutant was superior in fruit quality to the initial genotype. Two hydroxylase enzymes, converting α- and β-carotene to lutein and zeaxanthin, respectively, are known to exist in pepper and are encoded by two genes on chromosomes 3 and 6-CrtZchr03 and CrtZchr06. The molecular characterization of the mutant variety through locus-specific Polymerase chain reaction amplification, gene cloning and sequencing as well as expression was performed. Our results suggest that the increased ß-carotene accumulation in the mutant variety Oranzheva kapia results from a biosynthetic pathway breakdown due to deletion of CrtZchr03 gene.

COMT, CRTZ, and F3’H regulate glycyrrhizic acid biosynthesis in Glycyrrhiza uralensis hairy roots

“…There is a competition among the three pathways for production of these secondary metabolites in G. uralensis. Several lines of evidence have demonstrated that overexpression of CRTZ increases the utilization of β-carotene (Pollmann et al 2017), while knockout of CRTZ has an opposite effect (Tomlekova et al 2021). It is thus expected that an accumulation of β-carotene by the CRTZ knockout leads to a feedback inhibition of the MEP pathway, which in turn promotes the MVA pathway and the production of GA in G. uralensis.…”

Genetic Regulation, Environmental Cues, and Extraction Methods for Higher Yield of Secondary Metabolites in Capsicum

“…Zeaxanthin epoxidase ( ZEP ) mutants and silenced plants had higher total carotenoids and zeaxanthin and displayed orange-colored fruits in maturity . A candidate pseudo response regulator2 ( PRR2 ) was identified for the C1 locus that was crucial for carotenoid biosynthesis alongside functional PSY1 ( Y locus ) and CCS ( C2 locus ) in C. frutescens , C. chinense “Habanero”, and C. annuum “IT158782”. , Deletion mutations in α and β-carotene hydroxylase ( CrtZ chr3 and CrtZ chr6 ) genes led to higher α and β-carotene levels and are associated with orange color in mature fruits of pepper variety Oranzheva kapia . The PSY2 gene was found to complement PSY1 deletion mutation in C. annuum “MicroPep Yellow” in the basal carotenoid biosynthesis pathway .…”

“…57,58 Deletion mutations in α and β-carotene hydroxylase (CrtZ chr3 and CrtZ chr6 ) genes led to higher α and β-carotene levels and are associated with orange color in mature fruits of pepper variety Oranzheva kapia. 59 The PSY2 gene was found to complement PSY1 deletion mutation in C. annuum "MicroPep Yellow" in the basal carotenoid biosynthesis pathway. 35 A total of 38 homologous structural genes of the carotenoid biosynthetic pathway and 17 regulatory TFs were identified in C. annuum during transcriptome analysis.…”

Fast and High-Efficiency Synthesis of Capsanthin in Pepper by Transient Expression of Geminivirus

“…Two genes, CaLCYB1 and CaLCYB2, have been discovered in the pepper genome, and their expression found to be associated with the presence of carotenoids [11]. The study of five cultivars, including the mutant Oranzheva kapia, showed that two hydroxylase genes, encoding CrtZchr03 and CrtZchr06, are present in pepper on chromosomes 3 and 6, and that deletion of the CrtZchr03 gene resulted in an increase in β-carotene accumulation [12]. Cotransformation of the genes responsible for β-carotene, 4,4 -ketolase (CrtW) and β-carotene 3,3 -hydroxylase (CrtZ), has been utilized to engineer transgenic organisms capable of producing astaxanthin, a naturally occurring carotenoid pigment known for its antioxidant properties and vibrant red-orange coloration [13].…”