Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
Laboratory of Plant Physiology and Biotechnologies, Faculty of Sciences, University of Lomé, Lomé 01BP 1515, Togo.
Int J Mol Sci. 2023 Jan 5;24(2):1055. doi: 10.3390/ijms24021055.
Sesame is a promising oilseed crop that produces specific lignans of clinical importance. Hence, a molecular description of the regulatory mechanisms of lignan biosynthesis is essential for crop improvement. Here, we resequence 410 sesame accessions and identify 5.38 and 1.16 million SNPs (single nucleotide polymorphisms) and InDels, respectively. Population genomic analyses reveal that sesame has evolved a geographic pattern categorized into northern (NC), middle (MC), and southern (SC) groups, with potential origin in the southern region and subsequent introduction to the other regions. Selective sweeps analysis uncovers 120 and 75 significant selected genomic regions in MC and NC groups, respectively. By screening these genomic regions, we unveiled 184 common genes positively selected in these subpopulations for exploitation in sesame improvement. Genome-wide association study identifies 17 and 72 SNP loci for sesamin and sesamolin variation, respectively, and 11 candidate causative genes. The major pleiotropic SNP locus for lignans variation is located in the exon of the gene . Further analyses revealed that this locus was positively selected in higher lignan content sesame accessions, and the "C" allele is favorable for a higher accumulation of lignans. Overexpression of in sesame hairy roots significantly up-regulated the expression of , and most of the monolignol biosynthetic genes. Consequently, the lignans content was significantly increased, and the lignin content was slightly increased. Our findings provide insights into lignans and lignin regulation in sesame and will facilitate molecular breeding of elite varieties and marker-traits association studies.
芝麻是一种很有前途的油料作物，能产生具有临床重要意义的特定木脂素。因此，对木脂素生物合成的调控机制进行分子描述对于作物改良至关重要。在这里，我们对 410 个芝麻品种进行了重测序，分别鉴定出 538 万个和 1160 万个 SNP（单核苷酸多态性）和 InDels。群体基因组分析表明，芝麻的进化具有地理模式，可分为北方（NC）、中部（MC）和南方（SC）三个群体，起源于南部地区，随后传入其他地区。选择扫描分析揭示了 MC 和 NC 群体中分别有 120 个和 75 个显著的选择基因组区域。通过筛选这些基因组区域，我们揭示了这两个亚种群中 184 个共同的正选择基因，可用于芝麻改良。全基因组关联研究鉴定出 sesamin 和 sesamolin 变异的 17 个和 72 个 SNP 位点，以及 11 个候选因果基因。木质素变异的主要多效性 SNP 位点位于基因的外显子中。进一步分析表明，该位点在木质素含量较高的芝麻品种中受到正向选择，“C”等位基因有利于木质素的积累。在芝麻毛状根中过表达 ，显著上调了 和大多数木质素生物合成基因的表达。因此，木质素含量显著增加，木质素含量略有增加。我们的研究结果为芝麻中木质素和木质素的调控提供了新的见解，并将促进优良品种的分子育种和标记-性状关联研究。
