[1]

Manivannan A, Lee ES, Han K, Lee HE, Kim DS. 2020. Versatile nutraceutical potentials of watermelon—a modest fruit loaded with pharmaceutically valuable phytochemicals. Molecules 25:5258

doi: 10.3390/molecules25225258
[2]

Bangalore DV, McGlynn WG, Scott DD. 2008. Effects of fruit maturity on watermelon ultrastructure and intracellular lycopene distribution. Journal of Food Science 73:S222−S228

doi: 10.1111/j.1750-3841.2008.00778.x
[3]

Martin Ask N, Leung M, Radhakrishnan R, Lobo GP. 2021. Vitamin a transporters in visual function: a mini review on membrane receptors for dietary vitamin a uptake, storage, and transport to the eye. Nutrients 13:3987

doi: 10.3390/nu13113987
[4]

Alcaíno J, Baeza M, Cifuentes V. 2016. Carotenoid distribution in nature. In Carotenoids in Nature, ed. Stange C. Cham: Springer International Publishing. pp. 3−33 doi: 10.1007/978-3-319-39126-7_1

[5]

Johnson EJ. 2014. Role of lutein and zeaxanthin in visual and cognitive function throughout the lifespan. Nutrition Reviews 72:605−612

doi: 10.1111/nure.12133
[6]

Yuan P, Umer MJ, He N, Zhao S, Lu X, et al. 2021. Transcriptome regulation of carotenoids in five flesh-colored watermelons (Citrullus lanatus). BMC Plant Biology 21:203

doi: 10.1186/s12870-021-02965-z
[7]

Llorente B, Torres-Montilla S, Morelli L, Florez-Sarasa I, Matus JT, et al. 2020. Synthetic conversion of leaf chloroplasts into carotenoid-rich plastids reveals mechanistic basis of natural chromoplast development. Proceedings of the National Academy of Sciences of the United States of America 117:21796−21803

doi: 10.1073/pnas.2004405117
[8]

Xu J, Wang X, Cao H, Xu H, Xu Q, et al. 2017. Dynamic changes in methylome and transcriptome patterns in response to methyltransferase inhibitor 5-azacytidine treatment in citrus. DNA Research 24:509−522

doi: 10.1093/dnares/dsx021
[9]

Grassi S, Piro G, Lee JM, Zheng Y, Fei Z, et al. 2013. Comparative genomics reveals candidate carotenoid pathway regulators of ripening watermelon fruit. BMC Genomics 14:781

doi: 10.1186/1471-2164-14-781
[10]

Luo Z, Zhang J, Li J, Yang C, Wang T, et al. 2013. A STAY-GREEN protein SlSGR1 regulates lycopene and β-carotene accumulation by interacting directly with SlPSY1 during ripening processes in tomato. New Phytologist 198:442−452

doi: 10.1111/nph.12175
[11]

Ren Y, Han R, Ma Y, Li X, Deng C, et al. 2022. Transcriptomics integrated with metabolomics unveil carotenoids accumulation and correlated gene regulation in white and yellow-fleshed turnip (Brassica rapa ssp. rapa). Genes 13:953

doi: 10.3390/genes13060953
[12]

Kalladan R, Lasky JR, Sharma S, Kumar MN, Juenger TE, et al. 2019. Natural variation in 9-cis-epoxycartenoid dioxygenase 3 and ABA accumulation. Plant Physiology 179:1620−1631

doi: 10.1104/pp.18.01185
[13]

Chayut N, Yuan H, Saar Y, Zheng Y, Sun T, et al. 2021. Comparative transcriptome analyses shed light on carotenoid production and plastid development in melon fruit. Horticulture Research 8:112

doi: 10.1038/s41438-021-00547-6
[14]

Liang MH, He YJ, Liu DM, Jiang JG. 2021. Regulation of carotenoid degradation and production of apocarotenoids in natural and engineered organisms. Critical Reviews in Biotechnology 41:513−534

doi: 10.1080/07388551.2021.1873242
[15]

Yu H, Cui N, Guo K, Xu W, Wang H. 2023. Epigenetic changes in the regulation of carotenoid metabolism during honeysuckle flower development. Horticultural Plant Journal 9:577−588

doi: 10.1016/j.hpj.2022.11.003
[16]

Rao S, Cao H, O’Hanna FJ, Zhou X, Lui A, et al. 2024. Nudix hydrolase 23 post-translationally regulates carotenoid biosynthesis in plants. The Plant Cell 36:1868−1891

doi: 10.1093/plcell/koae030
[17]

Chayut N, Yuan H, Ohali S, Meir A, Sa’ar U, et al. 2017. Distinct mechanisms of the ORANGE protein in controlling carotenoid flux. Plant Physiology 173:376−389

doi: 10.1104/pp.16.01256
[18]

Zhou X, Sun T, Owens L, Yang Y, Fish T, et al. 2023. Carotenoid sequestration protein FIBRILLIN participates in CmOR-regulated β-carotene accumulation in melon. Plant Physiology 193:643−660

doi: 10.1093/plphys/kiad312
[19]

Fang X, Liu S, Gao P, Liu H, Wang X, et al. 2020. Expression of ClPAP and ClPSY1 in watermelon correlates with chromoplast differentiation, carotenoid accumulation, and flesh color formation. Scientia Horticulturae 270:109437

doi: 10.1016/j.scienta.2020.109437
[20]

Lu S, Van Eck J, Zhou X, Lopez AB, O'Halloran DM, et al. 2006. The cauliflower or gene encodes a DnaJ cysteine-rich domain-containing protein that mediates high levels of β-carotene accumulation. The Plant cell 18:3594−3605

[21]

Tzuri G, Zhou X, Chayut N, Yuan H, Portnoy V, et al. 2015. A ‘golden’ SNP in CmOr governs the fruit flesh color of melon (Cucumis melo). The Plant Journal 82:267−279

doi: 10.1111/tpj.12814
[22]

Li L, Paolillo DJ, Parthasarathy MV, DiMuzio EM, Garvin DF. 2001. A novel gene mutation that confers abnormal patterns of β-carotene accumulation in cauliflower (Brassica oleracea var. botrytis). The Plant Journal 26:59−67

doi: 10.1046/j.1365-313x.2001.01008.x
[23]

Wang Z, Xu W, Kang J, Li M, Huang J, et al. 2018. Overexpression of alfalfa Orange gene in tobacco enhances carotenoid accumulation and tolerance to multiple abiotic stresses. Plant Physiology and Biochemistry 130:613−622

doi: 10.1016/j.plaphy.2018.08.017
[24]

Berman J, Zorrilla-López U, Medina V, Farré G, Sandmann G, et al. 2017. The Arabidopsis ORANGE (AtOR) gene promotes carotenoid accumulation in transgenic corn hybrids derived from parental lines with limited carotenoid pools. Plant Cell Reports 36:933−945

doi: 10.1007/s00299-017-2126-z
[25]

Yazdani M, Sun Z, Yuan H, Zeng S, Thannhauser TW, et al. 2019. Ectopic expression of ORANGE promotes carotenoid accumulation and fruit development in tomato. Plant Biotechnology Journal 17:33−49

doi: 10.1111/pbi.12945
[26]

Kim SE, Lee CJ, Park SU, Lim YH, Park WS, et al. 2021. Overexpression of the golden SNP-carrying Orange gene enhances carotenoid accumulation and heat stress tolerance in sweetpotato plants. Antioxidants 10:51

doi: 10.3390/antiox10010051
[27]

Zhang L, Zhang S, Dai Y, Wang S, Wang C, et al. 2022. Mapping and validation of BrGOLDEN: a dominant gene regulating carotenoid accumulation in Brassica rapa. International Journal of Molecular Sciences 23:12442

doi: 10.3390/ijms232012442
[28]

Kang L, Zhang C, Liu J, Ye M, Zhang L, et al. 2023. Overexpression of potato ORANGE (StOR) and StOR mutant in Arabidopsis confers increased carotenoid accumulation and tolerance to abiotic stress. Plant Physiology and Biochemistry 201:107809

doi: 10.1016/j.plaphy.2023.107809
[29]

Rodriguez GA. 2001. Extraction, isolation, and purification of carotenoids. Current Protocols in Food Analytical Chemistry F2.1.1−F2.1.8

doi: 10.1002/0471142913.faf0201s00
[30]

Arnon DI. 1949. Copper enzymes in isolated chloroplasts. polyphenoloxidase in Beta Vulgaris. Plant Physiology 24:1−15

doi: 10.1104/pp.24.1.1
[31]

Xu R, Wang Y, Wang L, Zhao Z, Cao J, et al. 2023. PsERF1B-PsMYB10.1-PsbHLH3 module enhances anthocyanin biosynthesis in the flesh-reddening of amber-fleshed plum (cv. Friar) fruit in response to cold storage. Horticulture Research 10:uhad091

doi: 10.1093/hr/uhad091
[32]

Hu CD, Chinenov Y, Kerppola TK. 2002. Visualization of interactions among bZIP and Rel family proteins in living cells using bimolecular fluorescence complementation. Molecular Cell 9:789−798

doi: 10.1016/S1097-2765(02)00496-3
[33]

Kong Q, Yuan J, Gao L, Zhao S, Jiang W, et al. 2014. Identification of suitable reference genes for gene expression normalization in qRT-PCR analysis in watermelon. PLoS One 9:e90612

doi: 10.1371/journal.pone.0090612
[34]

Guo S, Zhao S, Sun H, Wang X, Wu S, et al. 2019. Resequencing of 414 cultivated and wild watermelon accessions identifies selection for fruit quality traits. Nature Genetics 51:1616−1623

doi: 10.1038/s41588-019-0518-4
[35]

Jin B, Jang G, Park G, Shahwar D, Shin J, et al. 2024. Development of a gene-based marker set for orange-colored watermelon flesh with a high β-carotene content. International Journal of Molecular Sciences 25:210

doi: 10.3390/ijms25010210
[36]

Tadmor Y, King S, Levi A, Davis A, Meir A, et al. 2005. Comparative fruit colouration in watermelon and tomato. Food Research International 38:837−841

doi: 10.1016/j.foodres.2004.07.011
[37]

Ilahy R, Tlili I, Siddiqui MW, Hdider C, Lenucci MS. 2019. Inside and beyond color: comparative overview of functional quality of tomato and watermelon fruits. Frontiers in Plant Science 10:769

doi: 10.3389/fpls.2019.00769
[38]

Lv P, Li N, Liu H, Gu H, Zhao WE. 2015. Changes in carotenoid profiles and in the expression pattern of the genes in carotenoid metabolisms during fruit development and ripening in four watermelon cultivars. Food Chemistry 174:52−59

doi: 10.1016/j.foodchem.2014.11.022
[39]

Sun T, Yuan H, Chen C, Kadirjan-Kalbach DK, Mazourek M, et al. 2020. ORHis, a natural variant of OR, specifically interacts with plastid division factor ARC3 to regulate chromoplast number and carotenoid accumulation. Molecular Plant 13:864−878

doi: 10.1016/j.molp.2020.03.007
[40]

Bartley GE, Scolnik PA. 1995. Plant carotenoids: pigments for photoprotection, visual attraction, and human health. The Plant Cell 7:1027−1038

doi: 10.2307/3870055
[41]

Harris WM, Spurr AR. 1969. Chromoplasts of tomato fruits. I. Ultrastructure of low-pigment and high-beta mutants. Carotene analyses. American Journal of Botany 56:369−379

doi: 10.1002/j.1537-2197.1969.tb07546.x
[42]

Schweiggert RM, Steingass CB, Heller A, Esquivel P, Carle R. 2011. Characterization of chromoplasts and carotenoids of red- and yellow-fleshed papaya (Carica papaya L.). Planta 234:1031−1044

doi: 10.1007/s00425-011-1457-1
[43]

Lado J, Zacarías L, Gurrea A, Page A, Stead A, et al. 2015. Exploring the diversity in Citrus fruit colouration to decipher the relationship between plastid ultrastructure and carotenoid composition. Planta 242:645−661

doi: 10.1007/s00425-015-2370-9
[44]

Kim JE, Rensing KH, Douglas CJ, Cheng KM. 2010. Chromoplasts ultrastructure and estimated carotene content in root secondary phloem of different carrot varieties. Planta 231:549−558

doi: 10.1007/s00425-009-1071-7
[45]

Sturaro M. 2025. Carotenoids in potato tubers: a bright yellow future ahead. Plants 14:272

doi: 10.3390/plants14020272
[46]

Morelli L, Torres-Montilla S, Glauser G, Shanmugabalaji V, Kessler F, et al. 2023. Novel insights into the contribution of plastoglobules and reactive oxygen species to chromoplast differentiation. New Phytologist 237:1696−1710

doi: 10.1111/nph.18585
[47]

Zhou X, Welsch R, Yang Y, Álvarez D, Riediger M, et al. 2015. Arabidopsis OR proteins are the major posttranscriptional regulators of phytoene synthase in controlling carotenoid biosynthesis. Proceedings of the National Academy of Sciences of the United States of America 112:3558−3563

doi: 10.1073/pnas.1420831112
[48]

Gong C, Diao W, Zhu H, Umer MJ, Zhao S, et al. 2021. Metabolome and transcriptome integration reveals insights into flavor formation of ‘Crimson’ watermelon flesh during fruit development. Frontiers in Plant Science 12:629361

doi: 10.3389/fpls.2021.629361
[49]

Anees M, Gao L, Umer MJ, Yuan P, Zhu H, et al. 2021. Identification of key gene networks associated with cell wall components leading to flesh firmness in watermelon. Frontiers in Plant Science 12:630243

doi: 10.3389/fpls.2021.630243
[50]

Yu Y, Yu J, Wang Q, Wang J, Zhao G, et al. 2021. Overexpression of the rice ORANGE gene OsOR negatively regulates carotenoid accumulation, leads to higher tiller numbers and decreases stress tolerance in Nipponbare rice. Plant Science 310:110962

doi: 10.1016/j.plantsci.2021.110962
[51]

Gao Y, Zhou X, Huang H, Wang C, Xiao X, et al. 2025. ORANGE proteins mediate adaptation to high light and resistance to Pseudomonas syringae in tomato by regulating chlorophylls and carotenoids accumulation. International Journal of Biological Macromolecules 306:141739

doi: 10.1016/j.ijbiomac.2025.141739
[52]

Lopez AB, Van Eck J, Conlin BJ, Paolillo DJ, O'Neill J, et al. 2008. Effect of the cauliflower Or transgene on carotenoid accumulation and chromoplast formation in transgenic potato tubers. Journal of Experimental Botany 59:213−223

doi: 10.1093/jxb/erm299
[53]

Bai C, Capell T, Berman J, Medina V, Sandmann G, et al. 2016. Bottlenecks in carotenoid biosynthesis and accumulation in rice endosperm are influenced by the precursor–product balance. Plant Biotechnology Journal 14:195−205

doi: 10.1111/pbi.12373
[54]

Oogo Y, Takemura M, Sakamoto A, Misawa N, Shimada H. 2022. Orange protein, phytoene synthase regulator, has protein disulfide reductase activity. Plant Signaling & Behavior 17:2072094

doi: 10.1080/15592324.2022.2072094
[55]

Nie H, Kim M, Lee S, Lim S, Lee MS, et al. 2023. High-quality genome assembly and genetic mapping reveal a gene regulating flesh color in watermelon (Citrullus lanatus). Frontiers in Plant Science 14:1142856

doi: 10.3389/fpls.2023.1142856
[56]

Liu S, Gao Z, Wang X, Luan F, Dai Z, et al. 2022. Nucleotide variation in the phytoene synthase (ClPsy1) gene contributes to golden flesh in watermelon (Citrullus lanatus L.). Theoretical and Applied Genetics 135:185−200

doi: 10.1007/s00122-021-03958-0
[57]

Sun T, Zhou F, Huang XQ, Chen WC, Kong MJ, et al. 2019. ORANGE represses chloroplast biogenesis in etiolated Arabidopsis Cotyledons via interaction with TCP14. The Plant Cell 31:2996−3014

doi: 10.1105/tpc.18.00290
[58]

Zhou X, Sun TH, Wang N, Ling HQ, Lu S, et al. 2011. The cauliflower Orange gene enhances petiole elongation by suppressing expression of eukaryotic release factor 1. New Phytologist 190:89−100

doi: 10.1111/j.1469-8137.2010.03578.x