Manchurian walnut (Juglans mandshurica Maxim.) is a synonym of J. cathayensis, a diploid, vulnerable, temperate deciduous tree valued for its wood and nut. It is also valued as a rootstock for Juglans regia because of its reported tolerance of lesion nematode. Reference genomes are available for several Juglans species, our goal was to produce a de novo, chromosome-level assembly of the J. mandshurica genome. Here, we reported an improved assembly of J. mandshurica with a contig N50 size of 6.49 Mb and a scaffold N50 size of 36.1 Mb. The total genome size was 548 Mb encoding 29,032 protein coding genes which were annotated. The collinearity analysis showed that J. mandshurica and J. regia originated from a common ancestor, with both species undergoing two WGD events. A genomic comparison showed that J. mandshurica was missing 1657 genes found in J. regia, and J. mandshurica includes 2827 genes not found in of the J. regia genome. The J. mandshurica contained 1440 unique paralogues that were highly enriched for flavonoid biosynthesis, phenylpropanoid biosynthesis, and plant-pathogen interaction. Four gene families related to disease resistance notable contraction (rapidly evolving; LEA, WAK, PPR, and PR) in J. mandshurica compared to eight species. JmaPR10 and JmaPR8 contained three orthologous gene pairs with J. regia that were highly expressed in root bark. JmaPR10 is a strong candidate gene for lesion nematodes resistance in J. mandshurica. The J. mandshurica genome should be a useful resource for study of the evolution, breeding, and genetic variation in walnuts (Juglans).

中文翻译：

---

改进脆弱的核桃树 Juglans mandshurica 的从头染色体水平基因组组装揭示了基因家族进化和对病斑线虫抗性的可能基因组基础

满洲胡桃（Juglans mandshurica Maxim.）是J的同义词。 cathayensis，一种二倍体，脆弱的，温带落叶树，因其木材和坚果而受到重视。由于据报道它对病斑线虫的耐受性，它也被认为是胡桃的砧木。参考基因组可用于几种胡桃树物种，我们的目标是产生J 的从头、染色体水平组装。 曼陀罗基因组。在这里，我们报告了J的改进组装。 曼陀罗contig N50 大小为 6.49 Mb，支架 N50 大小为 36.1 Mb。总基因组大小为 548 Mb，编码 29,032 个已注释的蛋白质编码基因。共线性分析表明J . mandshurica和J. regia起源于一个共同的祖先，两个物种都经历了两次 WGD 事件。基因组比较表明J . mandshurica缺失了在J. regia 中发现的 1657 个基因，而J . mandshurica包括 2827 基因未在J. regia基因组中发现。该Ĵ。 曼陀罗包含 1440 个独特的旁系同源物，它们高度富集类黄酮生物合成、苯丙烷生物合成和植物-病原体相互作用。J 中与抗病性显着收缩（快速进化；LEA、WAK、PPR和PR）相关的四个基因家族。 mandshurica与八个物种相比。JmaPR10和JmaPR8包括三个直系同源基因对与J.核桃其是高度在根皮中表达。JmaPR10是J病斑线虫抗性的强候选基因。 曼陀罗。该Ĵ. mandshurica基因组应该是研究核桃 ( Juglans )进化、育种和遗传变异的有用资源。