Abstract Detail

Population Genetics/Genomics

Mattingly, Kali [1], Hovick, Steve [2].

Synthesized autopolyploids of Arabidopsis are more plastic than their diploid progenitors.

Species must rapidly adapt or go extinct. Rapid adaptation has been driven in the past by large genomic rearrangements like whole genome duplication (WGD), and this process also continues to drive contemporary evolution. Though early scientists hypothesized that, compared to their diploid progenitors, polyploids occupied narrower niche space, more recent work using both ecological niche modeling and manipulative experiments has tended to support the hypothesis that WGD increases niche breadth, though the signal of this general pattern is moderated by demographic factors and other evolutionary processes operating in nature. To isolate the effects of WGD on traits, we conducted a common garden experiment comparing two diploid genotypes of Arabidopsis thaliana to corresponding autotetraploid lines synthesized in the lab. To make inferences about how trait variation may be associated with adaptation and niche breadth, we manipulated stressors in a factorial treatment design and measured phenotypic plasticity across these environments. We imposed nutrient and salt treatments, two stressors relevant to the biology of these stress-tolerant/ruderal taxa. We found considerable variation in phenotypes and stress responses across taxa, surprising given the low genetic diversity of A. thaliana. For all cases in which diploids and polyploids differed in plasticity, polyploids were more plastic, consistent with previous work indicating that polyploids have broader niches than their diploid progenitors. Increased plasticity in polyploids was often adaptive (associated with higher total seed mass) but showed some neutral relationships to fitness under stressful conditions. Whole genome duplication was about as likely to affect mean trait values as plasticities. For example, across all environmental conditions, we saw transgressively slow phenology in tetraploids compared to diploids, a pattern commonly observed as a consequence of WGD. Slowed phenology was adaptive in one polyploid genotype under amenable conditions, but was maladaptive in the other genotype under stress, highlighting context-dependency in the adaptive consequences of WGD. Our work shows that increased phenotypic plasticity can result from WGD alone, independent of other evolutionary processes like natural selection or hybridization, and will contribute to the understanding of how WGD has driven diversification and adaptation of lineages on both ancient and modern timescales.

1 - The Ohio State University, Evolution, Ecology & Organismal Biology, 318 W 12th Ave, 300 Aronoff Laboratory, Columbus, OH, 43210, USA
2 - The Ohio State University, Dept. Of Evolution, Ecology & Organismal Biology, 318 W. 12th Avenue, 300 Aronoff Laboratory, 318 W. 12th Avenue, Columbus, OH, 43210, United States

Keywords:
polyploidy
Arabidopsis
phenotypic plasticity
common garden
adaptation.

Presentation Type: Oral Paper
Session: POPGEN3, Population Genetics/Genomics III
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 10:45 AM
Number: POPGEN3004
Abstract ID:202
Candidate for Awards:Margaret Menzel Award