Convergent adaptation of the genomes of woody plants at the land-sea interface

• 作者: Cairong Zhong David E.Boufford Haomin Lyu Norman C.Duke Shaohua Xu Suhua Shi The International Mangrove Consortium Wuxia Guo Zhang Zhang Ziwen He
• 来源期刊: 国家科学评论（英文版）
• 关键词: convergent evolution genome mangrove adaptive evolution woody plants
• 年，卷（期）: 2020,（6）
• 页码范围: 978-993
• 页数: 16页
• 语种: 英文
• DOI: 10.1093/nsr/nwaa027

摘要

Sequencing multiple species that share the same ecological niche may be a new frontier for genomic studies.While such studies should shed light on molecular convergence,genomic-level analyses have been unsuccessful,due mainly to the absence of empirical controls.Woody plant species that colonized the global tropical coasts,collectively referred to as mangroves,are ideal for convergence studies.Here,we sequenced the genomes/transcriptomes of 16 species belonging in three major mangrove clades.To detect convergence in a large phylogeny,a CCS+ model is implemented,extending the more limited CCS method (convergence at conservative sites).Using the empirical control for reference,the CCS+ model reduces the noises drastically,thus permitting the identification of 73 convergent genes with Ptrue (probability of true convergence) ＞ 0.9.Products of the convergent genes tend to be on the plasma membrane associated with salinity tolerance.Importantly,convergence is more often manifested at a higher level than at amino-acid (AA) sites.Relative to ＞ 50 plant species,mangroves strongly prefer 4 AAs and avoid S others across the genome.AA substitutions between mangrove species strongly reflect these tendencies.In conclusion,the selection oftaxa,the number of species and,in particular,the empirical control are all crucial for detecting genome-wide convergence.We believe this large study of mangroves is the first successful attempt at detecting genome-wide site convergence.