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Article|01 Aug 2020|OPEN
Chromosome-scale genome assembly of sweet cherry (Prunus avium L.) cv. Tieton obtained using long-read and Hi-C sequencing
Jiawei Wang1, Weizhen Liu2, Dongzi Zhu1, Po Hong1, Shizhong Zhang3, Shijun Xiao2,4, Yue Tan1, Xin Chen1, Li Xu1, Xiaojuan Zong1, Lisi Zhang1, Hairong Wei1, Xiaohui Yuan2 & Qingzhong Liu1,
1Shandong Key Laboratory of Fruit Biotechnology Breeding, Shandong Institute of Pomology, Taian, Shandong 271000, China
2School of Computer Science and Technology, Wuhan University of Technology, Wuhan, Hubei 430070, China
3State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, Shandong 271018, China
4Gooal Gene, Wuhan, Hubei 430070, China

Horticulture Research 7,
Article number: 20122 (2020)
doi: 10.1038/hortres.2020.122
Views: 165

Received: 26 Mar 2020
Revised: 29 Apr 2020
Accepted: 12 May 2020
Published online: 01 Aug 2020

Abstract

Sweet cherry (Prunus avium) is an economically significant fruit species in the genus Prunus. However, in contrast to other important fruit trees in this genus, only one draft genome assembly is available for sweet cherry, which was assembled using only Illumina short-read sequences. The incompleteness and low quality of the current sweet cherry draft genome limit its use in genetic and genomic studies. A high-quality chromosome-scale sweet cherry reference genome assembly is therefore needed. A total of 65.05 Gb of Oxford Nanopore long reads and 46.24 Gb of Illumina short reads were generated, representing ~190x and 136x coverage, respectively, of the sweet cherry genome. The final de novo assembly resulted in a phased haplotype assembly of 344.29 Mb with a contig N50 of 3.25 Mb. Hi-C scaffolding of the genome resulted in eight pseudochromosomes containing 99.59% of the bases in the assembled genome. Genome annotation revealed that more than half of the genome (59.40%) was composed of repetitive sequences, and 40,338 protein-coding genes were predicted, 75.40% of which were functionally annotated. With the chromosome-scale assembly, we revealed that gene duplication events contributed to the expansion of gene families for salicylic acid/jasmonic acid carboxyl methyltransferase and ankyrin repeat-containing proteins in the genome of sweet cherry. Four auxin-responsive genes (two GH3s and two SAURs) were induced in the late stage of fruit development, indicating that auxin is crucial for the sweet cherry ripening process. In addition, 772 resistance genes were identified and functionally predicted in the sweet cherry genome. The high-quality genome assembly of sweet cherry obtained in this study will provide valuable genomic resources for sweet cherry improvement and molecular breeding.