Improved genome assembly provides new insights into genome evolution in a desert poplar (Populus euphratica)

Zhiyang Zhang, Yang Chen, Junlin Zhang, Xinzhi Ma, Yiling Li, Mengmeng Li, Deyan Wang, Minghui Kang, Haolin Wu, Yongzhi Yang, Matthew S. Olson, Stephen P. DiFazio, Dongshi Wan, Jianquan Liu, Tao Ma

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Populus euphratica is well adapted to extreme desert environments and is an important model species for elucidating the mechanisms of abiotic stress resistance in trees. The current assembly of P. euphratica genome is highly fragmented with many gaps and errors, thereby impeding downstream applications. Here, we report an improved chromosome-level reference genome of P. euphratica (v2.0) using single-molecule sequencing and chromosome conformation capture (Hi-C) technologies. Relative to the previous reference genome, our assembly represents a nearly 60-fold improvement in contiguity, with a scaffold N50 size of 28.59 Mb. Using this genome, we have found that extensive expansion of Gypsy elements in P. euphratica led to its rapid increase in genome size compared to any other Salicaceae species studied to date, and potentially contributed to adaptive divergence driven by insertions near genes involved in stress tolerance. We also detected a wide range of unique structural rearrangements in P. euphratica, including 2,549 translocations, 454 inversions, 121 tandem and 14 segmental duplications. Several key genes likely to be involved in tolerance to abiotic stress were identified within these regions. This high-quality genome represents a valuable resource for poplar breeding and genetic improvement in the future, as well as comparative genomic analysis with other Salicaceae species.

Original languageEnglish
Pages (from-to)781-794
Number of pages14
JournalMolecular Ecology Resources
Volume20
Issue number3
DOIs
StatePublished - May 1 2020

Keywords

  • Populus euphratica
  • environmental adaptation
  • genome assembly
  • repeat expansion
  • structural variation

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