Avocado (Persea americana) is a member of the magnoliids, an early branching lineage of angiosperms that has high value globally with the fruit being highly nutritious. Here, we report a chromosome-level genome assembly for the commercial avocado cultivar Hass, which represents 80% of the world’s avocado consumption. The DNA contigs produced from Pacific Biosciences HiFi reads were further assembled using a previously published version of the genome supported by a genetic map. The total assembly was 913 Mb with a contig N50 of 84 Mb. Contigs assigned to the 12 chromosomes represented 874 Mb and covered 98.8% of benchmarked single-copy genes from embryophytes. Annotation of protein coding sequences identified 48 915 avocado genes of which 39 207 could be ascribed functions. The genome contained 62.6% repeat elements. Specific biosynthetic pathways of interest in the genome were investigated. The analysis suggested that the predominant pathway of heptose biosynthesis in avocado may be through sedoheptulose 1,7 bisphosphate rather than via alternative routes. Endoglucanase genes were high in number, consistent with avocado using cellulase for fruit ripening. The avocado genome appeared to have a limited number of translocations between homeologous chromosomes, despite having undergone multiple genome duplication events. Proteome clustering with related species permitted identification of genes unique to avocado and other members of the Lauraceae family, as well as genes unique to species diverged near or prior to the divergence of monocots and eudicots. This genome provides a tool to support future advances in the development of elite avocado varieties with higher yields and fruit quality.

中文翻译：

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单倍型解析的染色体水平鳄梨基因组允许分析新的鳄梨基因

鳄梨 (Persea americana) 是木兰属的成员，木兰是被子植物的早期分支谱系，在全球范围内具有很高的价值，果实营养丰富。在这里，我们报告了商业鳄梨品种 Hass 的染色体水平基因组组装，该品种占世界鳄梨消费量的 80%。使用由遗传图谱支持的先前发布的基因组版本进一步组装从 Pacific Biosciences HiFi 读取产生的 DNA 重叠群。总组装量为 913 Mb，contig N50 为 84 Mb。分配给 12 条染色体的重叠群代表 874 Mb，覆盖了 98.8% 的来自胚胎植物的基准单拷贝基因。蛋白质编码序列的注释确定了 48 915 个鳄梨基因，其中 39 207 个可归因于功能。基因组包含 62.6% 的重复元素。研究了基因组中感兴趣的特定生物合成途径。分析表明，鳄梨中庚糖生物合成的主要途径可能是通过景庚酮糖 1,7 二磷酸，而不是通过替代途径。内切葡聚糖酶基因数量较多，这与使用纤维素酶进行果实成熟的鳄梨一致。尽管经历了多次基因组复制事件，鳄梨基因组似乎在同源染色体之间具有有限数量的易位。与相关物种的蛋白质组聚类允许鉴定鳄梨和月桂科其他成员特有的基因，以及在单子叶植物和真双子叶植物分化附近或之前分化的物种独有的基因。