背景回顾：Maples (the genus Acer) represent important and beloved forest, urban, and ornamental trees distributed throughout the Northern hemisphere. They exist in a diverse array of native ranges and distributions, across spectrums of tolerance or decline, and have varying levels of susceptibility to biotic and abiotic stress. Among Acer species, several stand out in their importance to economic interest. 

主要研究：Here we report the first two chromosome-scale genomes for North American species,Acer negundo and Acer saccharum. 

结果1-组装：Both assembled genomes contain scaffolds corresponding to 13 chromosomes, with A. negundo at a length of 442 Mb, N50 of 32 Mb and 30,491 genes, and A. saccharum at 626 Mb, N50 of 46 Mb, and 40,074 genes. 

结果2-WGD和TE爆发：No recent whole genome duplications were detected, though A. saccharum has local gene duplication and more recent bursts of transposable elements, as well as a large-scale translocation between two chromosomes. 

结果3-基因家族扩张和收缩：Genomic comparison revealed that A. negundo has a smaller genome with recent gene family evolution that is predominantly contracted and expansions that are potentially related to invasive tendencies and tolerance to abiotic stress. 

结果4-RNA-seq：Examination of expression from RNA-Seq obtained from A. saccharum grown in long-term aluminum and calcium soil treatments at the Hubbard Brook Experimental Forest, provided insights into genes involved in aluminum stress response at the systemic level, as well as signs of compromised processes upon calcium deficiency, a condition contributing to maple decline.

 摘 要 

槭树是一类重要的森林、城市和园艺栽培树种，在北半球广泛分布。槭树的自然分布范围十分广泛，覆盖了各种不同的胁迫生境或不同的群体衰退水平，对于生物和非生物胁迫具有各种水平的敏感性。在槭树属的物种中，有一些因其具有重要的经济价值而出名。本文中，作者首次报道了两个北美槭树物种的染色体级别基因组，分别是梣叶槭（Acer negundo）和糖槭（Acer saccharum）。这两个槭树的基因组组装都具有与13条染色体数量相对应的scaffolds数。其中，梣叶槭基因组组装大小442 Mb，N50长32 Mb，共注释30,491个基因；糖槭基因组组装大小626 Mb，N50长46 Mb，共注释40,074个基因。这两个槭树基因组上并未检测到全基因组复制的信号，但是糖槭具有局部的基因复制事件以及最近的转座子爆发事件，以及染色体间的大规模易位。比较基因组分析显示梣叶槭的基因组较小，并且最近的基因家族演化主要发生的收缩，在发生扩张基因家族中主要与入侵倾向以及非生物胁迫抗性相关。通过对Hubbard Brook实验林中长期铝和钙土壤处理中生长的糖槭RNA-Seq分析，深入揭示了糖槭系统水平上的铝胁迫响应相关基因，以及缺钙过程生长受损的迹象，这可能是槭树群体衰退的原因。