The chromosome-scale assembly of the willow genome provides insight into Salicaceae genome evolution

First author: Suyun Wei; Affiliations: Nanjing Forestry University (南京林业大学): Nanjing, China

Corresponding author: Tongmin Yin

Salix suchowensis is an early-flowering shrub willow that provides a desirable system for studies on the basic biology of woody plants. The current reference genome of S. suchowensis was assembled with 454 sequencing reads. Here, we report a chromosome-scale assembly of S. suchowensis generated by combining PacBio sequencing with Hi-C technologies. The obtained genome assemblies covered a total length of 356 Mb. The contig N50 of these assemblies was 263,908 bp, which was ~65-fold higher than that reported previously. The contiguity and completeness of the genome were significantly improved. By applying Hi-C data, 339.67 Mb (95.29%) of the assembled sequences were allocated to the 19 chromosomes of haploid willow. With the chromosome-scale assembly, we revealed a series of major chromosomal fissions and fusions that explain the genome divergence between the sister genera of Salix and Populus. The more complete and accurate willow reference genome obtained in this study provides a fundamental resource for studying many genetic and genomic characteristics of woody plants.

簸箕柳（学名：Salix suchowensis）是一种早花灌木柳，是木本植物基础生物学研究的理想系统。目前的簸箕柳参考基因组是通过454测序reads组装而成的。本文中，作者通过结合三代PacBio测序和高通量染色体构象捕获Hi-C技术获得了染色体级别的簸箕柳基因组组装。新获得的簸箕柳基因组全长356 Mb，Contig N50长263,908  bp，是先前版本的65倍。新版本的基因组组装在连续性和完整性上都有了较大的提升。通过应用Hi-C技术，95.29%的簸箕柳基因组组装能够挂载到19条染色体上。基于染色体层面的基因组组装，作者揭示了一系列的染色体裂变（fissions）和融合（fusions），解释了柳属与杨属两个姊妹属之间的基因组分化。本文所获得的更加完整、精确的柳树参考基因组为木本植物的遗传和基因组研究提供了基础。

通讯：尹佟明 (http://linxue.njfu.edu.cn/info.php?cid=117)

个人简介：1997年，南京林业大学，博士；2000-2001年，瑞典农业大学，博士后；2002-2005年，美国能源部橡树岭国家实验室，博士后。

研究方向：林木遗传育种、分子数量遗传学、林木基因组与生物信息学。

doi: https://doi.org/10.1038/s41477-020-0622-6

Journal: Horticulture Research

Published date: April 01, 2020