Ro Nayoung, Oh Hyeonseok, Ko Ho-Cheol, Yi Jungyoon, Na Young-Wang, Haile Mesfin
National Agrobiodiversity Center, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Republic of Korea.
Plants (Basel). 2024 Sep 12;13(18):2562. doi: 10.3390/plants13182562.
This study investigated carotenoid content and fruit color variation in 306 pepper accessions from diverse species. Red-fruited accessions were predominant (245 accessions), followed by orange (35) and yellow (20). Carotenoid profiles varied significantly across accessions, with capsanthin showing the highest mean concentration (239.12 μg/g), followed by β-cryptoxanthin (63.70 μg/g) and zeaxanthin (63.25 μg/g). Total carotenoid content ranged from 7.09 to 2566.67 μg/g, emphasizing the diversity within the dataset. Correlation analysis revealed complex relationships between carotenoids, with strong positive correlations observed between total carotenoids and capsanthin (r = 0.94 ***), β-cryptoxanthin (r = 0.87 ***), and zeaxanthin (r = 0.84 ***). Principal component analysis (PCA) identified two distinct carotenoid groups, accounting for 67.6% of the total variance. A genome-wide association study (GWAS) identified 91 significant single nucleotide polymorphisms (SNPs) associated with fruit color (15 SNPs) and carotenoid content (76 SNPs). These SNPs were distributed across all chromosomes, with varying numbers on each. Among individual carotenoids, α-carotene was associated with 28 SNPs, while other carotenoids showed different numbers of associated SNPs. Candidate genes encoding diverse proteins were identified near significant SNPs, potentially contributing to fruit color variation and carotenoid accumulation. These included pentatricopeptide repeat-containing proteins, mitochondrial proton/calcium exchangers, E3 ubiquitin-protein ligase SINAT2, histone-lysine N-methyltransferase, sucrose synthase, and various enzymes involved in metabolic processes. Seven SNPs exhibited pleiotropic effects on multiple carotenoids, particularly β-cryptoxanthin and capsanthin. The findings of this study provide insights into the genetic architecture of carotenoid biosynthesis and fruit color in peppers, offering valuable resources for targeted breeding programs aimed at enhancing the nutritional and sensory attributes of pepper varieties.
本研究调查了来自不同物种的306份辣椒种质的类胡萝卜素含量和果实颜色变异。红色果实的种质占主导（245份），其次是橙色（35份）和黄色（20份）。不同种质的类胡萝卜素谱差异显著，辣椒红素的平均浓度最高（239.12μg/g），其次是β-隐黄质（63.70μg/g）和玉米黄质（63.25μg/g）。总类胡萝卜素含量在7.09至2566.67μg/g之间，突出了数据集中的多样性。相关性分析揭示了类胡萝卜素之间的复杂关系，总类胡萝卜素与辣椒红素（r = 0.94 ***）、β-隐黄质（r = 0.87 ***）和玉米黄质（r = 0.84 ***）之间存在强正相关。主成分分析（PCA）确定了两个不同的类胡萝卜素组，占总变异的67.6%。全基因组关联研究（GWAS）确定了91个与果实颜色（15个单核苷酸多态性）和类胡萝卜素含量（76个单核苷酸多态性）相关的显著单核苷酸多态性（SNP）。这些SNP分布在所有染色体上，每条染色体上的数量各不相同。在单个类胡萝卜素中，α-胡萝卜素与28个SNP相关，而其他类胡萝卜素显示出不同数量的相关SNP。在显著SNP附近鉴定出编码多种蛋白质的候选基因，可能对果实颜色变异和类胡萝卜素积累有贡献。这些包括含五肽重复序列的蛋白质、线粒体质子/钙交换器、E3泛素蛋白连接酶SINAT2、组蛋白赖氨酸N-甲基转移酶、蔗糖合酶以及参与代谢过程的各种酶。七个SNP对多种类胡萝卜素，特别是β-隐黄质和辣椒红素表现出多效性作用。本研究结果为辣椒类胡萝卜素生物合成和果实颜色的遗传结构提供了见解，为旨在改善辣椒品种营养和感官特性的定向育种计划提供了宝贵资源。
