Japanese apricot (Prunus mume) is an attractive fruit tree originating from China, and its cultivation history dates back 7000 years. In this study, we investigated the genetic diversity, population structure, and genetic relationship of Japanese apricots in different regions of China and Japan. The analyses of the genetic variation between wild and cultivated populations improved our understanding of the general mechanisms of domestication and improvement. A total of 146 accessions of Japanese apricot from different geographic locations were sequenced. The genetic diversity of wild and domesticated accessions (3.60 × 10-3 and 3.51 × 10-3 , respectively) from China was high, and the effect of artificial selection pressure on domesticated accessions was small; however, the genetic diversity of artificially bred accessions decreased significantly (2.68 × 10-3 ) compared to domesticated accessions, which had an obvious improvement bottleneck effect. The chloroplast genome results showed that 41 haplotypes were detected, and Japanese apricots from the Yunnan region had the most haplotypes and the highest genetic diversity. The results revealed the dissemination route of Japanese apricot, not only along the Yangtze River basin system (from southwest China to Hunan, Jiangxi, and Anhui, and finally to the Jiangsu, Zhejiang, and Shanghai areas). Additionally, we discovered a second route for Japanese apricot dispersion, which was mostly in the Pearl River basin system, from southwest China to Libo of Guizhou and then to the Guangdong, Fujian, and Taiwan areas. This also showed that Japanese-bred accessions originated from Zhejiang, China. In addition, selective sweep analysis showed that most of the high-impact single nucleotide polymorphisms were identified in genes related to glucose metabolism, aromatic compound metabolism, flowering time, dormancy, and resistance to abiotic stress during the domestication and improvement of Japanese apricot.
Keywords: Japanese apricot; chloroplast genome; genome resequencing; population structure; selective sweep analysis.
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