Abstract Detail

Phylogenomics

Wang, Ning [1], Yang, Ya [2], Moore, Michael J. [3], Brockington, Samuel [4], Walker, Joseph [1], Brown, Joseph [5], Eggli, Urs [6], Majure, Lucas [7], Smith, Stephen [8].

Evolution of Portulacineae marked by gene tree conflict and gene family expansion associated with adaptation to harsh environments.

Survival in harsh environments is associated with several adaptations in plants. Species in the Portulacineae (Caryophyllales) have adapted to some of the most extreme terrestrial conditions on Earth, including extreme heat, cold, and salinity. Here, we generated 52 new transcriptomes and combined these with 30 previously generated transcriptomes, forming a dataset containing 68 species of Portulacinaeae, seven from its sister clade Molluginaceae, and seven outgroups. We performed a phylotranscriptomic analysis to examine patterns of molecular evolution within the Portulacineae. Our inferred species tree topology was largely congruent with previous analyses. We also identified several nodes that were characterized by excessive gene tree conflict and examined the potential influence of outlying genes. We identified gene duplications throughout the Portulacineae, and found corroborating evidence for previously identified paleopolyploidy events along with one newly identified event associated with the family Didiereaceae. Gene family expansion within Portulacineae was associated with genes previously identified as important for survival in extreme conditions, indicating possible molecular correlates of niche changes that should be explored further. Some of these genes also showed some evidence for positive selection. The correlation between gene function and expansion suggests that gene/genome duplication have likely contributed to the extreme adaptations seen in the Portulacineae.

1 - University of Michigan, Ecology and Evolutionary Biology, 830 North University avenue, Ann arbor, MI, 48109, United States
2 - University Of Minnesota, Plant And Microbial Biology, 1445 Gortner Avenue, St. Paul, MN, 55108, United States
3 - Oberlin College, Department Of Biology, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, United States
4 - Downing Site, Cambridge, CB23AE, UK
5 - University of Sheffield, Animal and Plant Sciences, Western Bank, Sheffield, UK
6 - Sukkulenten-Sammlung Zürich, Mythenquai 88, CH-8002 Zürich, Switzerland
7 - Desert Botanical Garden, 1201 N. Galvin Pkwy, Phoenix, AZ, 85008, United States
8 - University of Michigan, Ecology and Evolutionary Biology, 2071A Kraus Natural Science Building, Ann Arbor, MI, 48109, USA

Keywords:
gene tree conflict
gene duplication
molecular evolution
paleopolyploidy
Portulacineae
stress adaptation.

Presentation Type: Oral Paper
Session: 1, Phylogenomics I
Location: 114/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 9:00 AM
Number: 1005
Abstract ID:191
Candidate for Awards:None