Wang Ruyu, Li Wei, He Qiang, Zhang Hongyu, Wang Meijia, Zheng Xinyuan, Liu Ze, Wang Yu, Du Cailian, Du Huilong, Xing Longsheng
College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071000, China.
Hebei Basic Science Center for Biotic Interaction, Institute of Life Sciences and Green Development, Hebei University, Baoding 071000, China.
Hortic Res. 2023 Jun 2;10(8):uhad120. doi: 10.1093/hr/uhad120. eCollection 2023 Aug.
Okra () is an important vegetable crop with high nutritional value. However, the mechanism underlying its high nutrient content remains poorly understood. Here, we present a chromosome-scale genome of okra with a size of 1.19 Gb. Comparative genomics analysis revealed the phylogenetic status of , as well as whole-genome duplication (WGD) events that have occurred widely across the Malvaceae species. We found that okra has experienced three additional WGDs compared with the diploid cotton , resulting in a large chromosome number (2n = 130). After three WGDs, okra has undergone extensive genomic deletions and retained substantial numbers of genes related to secondary metabolite biosynthesis and environmental adaptation, resulting in significant differences between okra and in the gene families related to cellulose synthesis. Combining transcriptomic and metabolomic analysis, we revealed the relationship between gene expression and metabolite content change across different okra developmental stages. Furthermore, the sinapic acid/S-lignin biosynthesis-related gene families have experienced remarkable expansion in okra, and the expression of key enzymes involved in the sinapic acid/S-lignin biosynthesis pathway vary greatly across developmental periods, which partially explains the differences in metabolite content across the different stages. Our study gains insights into the comprehensive evolutionary history of Malvaceae species and the genetic basis that underlies the nutrient content changes in okra, which will facilitate the functional study and genetic improvement of okra varieties.
秋葵（）是一种具有高营养价值的重要蔬菜作物。然而，其高营养成分背后的机制仍知之甚少。在此，我们展示了一个大小为1.19Gb的秋葵染色体水平基因组。比较基因组学分析揭示了秋葵的系统发育地位，以及在锦葵科物种中广泛发生的全基因组复制（WGD）事件。我们发现，与二倍体棉花相比，秋葵经历了三次额外的WGD，导致染色体数目庞大（2n = 130）。经过三次WGD后，秋葵经历了广泛的基因组缺失，并保留了大量与次生代谢物生物合成和环境适应相关的基因，导致秋葵与棉花在纤维素合成相关基因家族上存在显著差异。结合转录组学和代谢组学分析，我们揭示了不同秋葵发育阶段基因表达与代谢物含量变化之间的关系。此外，芥子酸/S-木质素生物合成相关基因家族在秋葵中经历了显著扩张，芥子酸/S-木质素生物合成途径中关键酶的表达在不同发育时期差异很大，这部分解释了不同阶段代谢物含量的差异。我们的研究深入了解了锦葵科物种的全面进化历史以及秋葵营养成分变化的遗传基础，这将有助于秋葵品种的功能研究和遗传改良。
