Abstract Detail

From Genes to Distributions: physiological ecology as an integrator of polyploid biology

Simonin , Kevin A [1], Roddy, Adam [2], Theroux-Rancourt, Guillaume [3], Jiang, Guo-Feng [4].

Simple scaling rules that link genome size to photosynthetic metabolism.

Polyploidy is a common phenomenon throughout the evolutionary history of terrestrial plants, especially among angiosperms, and is associated with a wide range of phenotypic innovations.  One consequence of whole genome duplication is a rapid increase in genome size. In addition to providing more gene copies for selection, duplication also increases the physical size of the genome and the space it occupies in the cell.  Here we show that the simple requirement that a cell contains its genome acts as a first order constraint on leaf structure and function and may scale up to influence ecological and evolutionary dynamics.  Because mature cells are generally lager than their meristematic precursors, genome size defines minimum cell size and maximum cell packing densities.  We show that genome size limitations on cell and tissue structure influence not only stomata and veins but also the mesophyll cells and tissues where CO2 fixation occurs.  Because smaller cells have a higher ratio of surface area to volume, smaller genomes allow for higher rates of CO2 diffusion through the stomata and into the mesophyll cells.  The biophysical limitations to CO2 uptake and leaf water loss that are defined by cell and tissue structure represent a first order control over photosynthetic metabolism per unit leaf area and, by extension, the maximum amount of carbon available for growth, reproduction, and defense.  Processes such as whole genome duplications that lead to increases in genome size also lead to decreases in rates of CO2 diffusion, i.e. decreases in stomatal conductance and mesophyll conductance.  Insofar as metabolic rate influences species’ ecological performance, changes in genome size have significant consequences for plant species distributions, ecological strategies, and evolutionary dynamics.  The strong links between genome size, minimum cell size, and diffusional limitations to photosynthetic metabolism suggest that any abiotic or biotic factor affecting maximum potential photosynthetic metabolism is also a potential agent of selection on genome size.

Related Links:

1 - San Francisco State University, Biology Department, 1600 Holloway Ave, Hensill Hall 538, San Francisco, CA, 94132, USA
2 - Yale University, Forestry & Environmental Studies, 370 Prospect St, New Haven, CT, 06511, United States
3 - University of Natural Resources and Life Sciences, Institute of Botany, Vienna, Austria
4 - Guangxi University, College of Forestry, Nanning, China

genome size.

Presentation Type: Symposium Presentation
Session: SY3, From Genes to Distributions: physiological ecology as an integrator of polyploid biology
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 12:30 PM
Number: SY3005
Abstract ID:716
Candidate for Awards:None

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