Investigation of genetic factors regulating chlorophyll and carotenoid biosynthesis in red pepper fruit

Abstract

Chlorophylls and carotenoids are synthesized in the chloroplast and chromoplast, respectively. Even though the two pigments are generated from the same precursor, the genetic correlation between chlorophyll and carotenoid biosynthesis has not yet been fully understood. We investigated the genetic correlation of chlorophyll and carotenoid biosynthesis during fruit ripening. Two recombinant inbred lines populations, "Long Sweet" × "AC2212" ("LA") RILs derived from a cross between Capsicum annuum "Long Sweet" with light-green and light-red fruit and C. annuum "AC2212" with dark-green and brown-fruit and "3501 (F)" × "3509 (C)" ("FC") RILs from C. annuum "3501" with dark-green and dark-red fruit and C. annuum "3509" with intermediate green and light-red fruit, were used. As the fruit ripened, three accessions produced high levels of xanthophyll. The dark-green immature fruit accumulated more total carotenoids than the light-green fruit. This trend corresponded to the expression pattern of 1-deoxy-d-xylulose 5phosphate synthase (DXS) and CaGLK2 genes during fruit development. The expression levels of DXS and CaGLK2 in the dark-green accession "3501" were significantly higher than those of "3509" and "Long Sweet" during the early stages of fruit development. Furthermore, the genotype analysis of the transcription factor controlling chloroplast development (CaGLK2) in LA RILs revealed that CaGLK2 expression affected both carotenoid and chlorophyll contents. The single nucleotide polymorphism (SNP) linkage maps were constructed using genotyping-by-sequencing (GBS) for the two populations, and QTL analysis was performed for green fruit color intensity and carotenoid content. The QTL (LA_BG-CST10) for capsanthin content in LA RILs located at 24.4 to 100.4 Mbp on chromosome 10 was overlapped with the QTL (FC15-Cap10) for capsanthin content in FC RILs. Three QTLs for capsanthin content, American spice trade association (ASTA) value, and immature green fruit color intensity were also overlapped from 178.2 to 204 Mbp on chromosome 10. At the location, 151.6 to 165 Mbp on chromosome 8, QTLs (FC15-tcar8, FC17-ASTA8.1, and FC17-ASTA8.2) for total carotenoid content Frontiers in Plant Science 01 frontiersin.org Jang et al. 10.3389/fpls.2022.922963and ASTA value were discovered, and this region contained 2-C-methyl-derythritol 4-phosphate cytidylyltransferase (MCT), which is involved in the MEP pathway. This result is the first report to show the correlation between carotenoid and chlorophyll biosynthesis in pepper. This research will expand our understanding of the mechanism of the chloroplast-to-chromoplast transition and the development of high pigment pepper varieties. KEYWORDSfruit color intensity, plastid conversion, chlorophylls, carotenoids, quantitative trait locus (QTL), Capsicum annuum (Pepper) LIKE1; CcLOL1) (Borovsky et al., 2019). The color of mature pepper fruit ranges from ivory to dark red depending on carotenoid composition. Hurtado-Hernandez and Smith (1985) suggested the three-loci model for mature pepper fruit ...

Regulation of Carotenoid Biosynthesis and Degradation in Lettuce (Lactuca sativa L.) from Seedlings to Harvest

“…Indeed, DXS expression levels were significantly reduced in all genotypes compared to other tested genes, suggesting a significant reduction in pigment synthesis in older tissues (Figure 6). Similar DXS reduction during developmental stages was observed in red pepper fruits [56].…”

Characterization of leucine aminopeptidase (LAP) activity in sweet pepper fruits during ripening and its inhibition by nitration and reducing events

“…On the contrary, the ripening process of pepper fruits involves many changes at the phenotypic, transcriptomic, proteomic, and metabolomic levels, and its big genome size, in comparison to other Solanaceae, makes its analysis complex (Dyachenko et al 2020 ; Razo-Mendivil et al 2021 ; Esposito et al 2022 ; Kovács et al 2022 ; Del Giúdice et al 2023 ). Recently, “omic” approaches have been carried out to study specific aspects of the ripening process (Chiaiese et al 2019 ; Dubey et al 2019 ; Zuo et al 2019 ; Lopez-Ortiz et al 2021 ; Rödiger et al 2021 ; Momo et al 2022 ; Villa-Rivera et al 2022 ; Song et al 2022 ; Liu et al 2023 ; Wang et al 2024 ) which are dependent on the variety, environmental growth conditions, fruit position, and ripening stage (Ribes-Moya et al 2020 ; Jang et al 2022 ; Lahbib et al 2023 ; Guijarro-Real et al 2023 ; Islam et al 2023 ). Despite the increase in information on the ripening of pepper fruits, to our knowledge, there is no data on the LAP in this process.…”

Enzyme-Based Biostimulants Influence Physiological and Biochemical Responses of Lactuca sativa L.

“…Quantitative evaluation of pigments revealed that Xylanase was the only BS solution that significantly impacted on chlorophyll and carotenoid content resulting in altered Chl a:b and Chls:Car ratios. The decrease in Chl b may be due to its conversion into Chl a, via the so-called "chlorophyll cycle" [40] to optimize adaptation of plants to varying light conditions [41][42][43][44]. The chlorophyll a:b ratio is a highly stable value that is generally used as a parameter to monitor plant oxidative stress status/tolerance because it is decreased by oxidative damage, according to its severity [45].…”

“…Nevertheless, given the stable levels of Chl a alongside an increase in Car, it is more plausible that Chl b is either degraded or transformed into carotenoids. This assumption is based on the shared precursor of both chlorophylls and carotenoids, namely GGPP (geranyl geranyl pyrophosphate) [43]. The rise in carotenoid content has been commonly reported in plants treated with several types of BSs [47,48].…”