The spinach YY genome reveals sex chromosome evolution, domestication, and introgression history of the species

作者：Xiaokai Ma, Liang Yu, Mahpara Fatima, William H. Wadlington, Amanda M. Hulse‐Kemp, Xingtan Zhang, Shengcheng Zhang, Xindan Xu, Jingjing Wang, Huaxing Huang, Jing Lin, Ban Deng, Zhenyang Liao, Zhenhui Yang, Yanhong Ma, Haibao Tang, Allen Van Deynze, Ray Ming · 发表于：Genome biology · 年份：2022 · DOI：10.1186/s13059-022-02633-x · 被引用次数：53 · 研究领域：Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities、Genetic and Environmental Crop Studies、Plant Reproductive Biology

BACKGROUND: Spinach (Spinacia oleracea L.) is a dioecious species with an XY sex chromosome system, but its Y chromosome has not been fully characterized. Our knowledge about the history of its domestication and improvement remains limited. RESULTS: A high-quality YY genome of spinach is assembled into 952 Mb in six pseudo-chromosomes. By a combination of genetic mapping, Genome-Wide Association Studies, and genomic analysis, we characterize a 17.42-Mb sex determination region (SDR) on chromosome 1. The sex chromosomes of spinach evolved when an insertion containing sex determination genes occurred, followed by a large genomic inversion about 1.98 Mya. A subsequent burst of SDR-specific repeats (0.1-0.15 Mya) explains the large size of this SDR. We identify a Y-specific gene, NRT1/PTR 6.4 which resides in this insertion, as a strong candidate for the sex determination or differentiation factor. Resequencing of 112 spinach genomes reveals a severe domestication bottleneck approximately 10.87 Kya, which dates the domestication of spinach 7000 years earlier than the archeological record. We demonstrate that a strong selection signal associated with internode elongation and leaf area expansion is associated with domestication of edibility traits in spinach. We find that several strong genomic introgressions from the wild species Spinacia turkestanica and Spinacia tetrandra harbor desirable alleles of genes related to downy mildew resistance, frost resistance, leaf morphology, and...