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Widespread ancient whole‐genome duplications in Malpighiales coincide with Eocene global climatic upheaval
Author(s) -
Cai Liming,
Xi Zhenxiang,
Amorim André M.,
Sugumaran M.,
Rest Joshua S.,
Liu Liang,
Davis Charles C.
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15357
Subject(s) - biology , extinction event , clade , evolutionary biology , aridification , plant evolution , phylogenetic tree , phylogenomics , phylogenetics , paleontology , genome , gene , genetics , biological dispersal , arid , population , demography , sociology
Summary Whole‐genome duplications ( WGD s) are widespread and prevalent in vascular plants and frequently coincide with major episodes of global and climatic upheaval, including the mass extinction at the Cretaceous–Tertiary boundary ( c . 65 Ma) and during more recent periods of global aridification in the Miocene ( c . 10–5 Ma). Here, we explore WGD s in the diverse flowering plant clade Malpighiales. Using transcriptomes and complete genomes from 42 species, we applied a multipronged phylogenomic pipeline to identify, locate, and determine the age of WGD s in Malpighiales using three means of inference: distributions of synonymous substitutions per synonymous site ( K s ) among paralogs, phylogenomic (gene tree) reconciliation, and a likelihood‐based gene‐count method. We conservatively identify 22 ancient WGD s, widely distributed across Malpighiales subclades. Importantly, these events are clustered around the Eocene–Paleocene transition ( c . 54 Ma), during which time the planet was warmer and wetter than any period in the Cenozoic. These results establish that the Eocene Climatic Optimum likely represents a previously unrecognized period of prolific WGD s in plants, and lends further support to the hypothesis that polyploidization promotes adaptation and enhances plant survival during episodes of global change, especially for tropical organisms like Malpighiales, which have tight thermal tolerances.