Abstract Detail

Molecular Ecology

Groen, Simon [1], Calic, Irina [2], Joly-Lopez, Zoe [3], Choi, Jae Young [3], Franks, Steven [4], Purugganan, Michael [3].

The strength and pattern of natural selection on rice gene expression.

Levels of gene expression underpin organismal phenotypes, yet the nature of selection on gene expression, and its role in adaptive evolution, remain elusive. We assayed gene expression in rice Oryza sativa, and used phenotypic selection analysis to estimate the type and strength of selection on levels of >15,000 transcripts. Variation in most transcripts appears neutral/near-neutral or under very weak stabilizing selection in wet paddy conditions, with median standardized selection differentials near zero, but greater under drought. More transcripts look to be conditionally neutral (2.83%) than antagonistically pleiotropic (0.04%). Also, transcripts displaying lower levels of expression and stochastic noise and higher levels of plasticity were under stronger selection. Selection strength was further weakly negatively associated with levels of cis-regulation, and network connectivity. Multivariate analysis suggests that selection acts on the expression of photosynthesis genes, but that its efficacy is genetically constrained under drought. Drought selected for earlier flowering and higher expression of OsMADS18, a known regulator of early flowering, marking this MADS-box transcription factor as a drought escape gene. The ability to estimate selection strengths provides insights into how selection can shape molecular traits at the core of gene action.

1 - New York University, Biology, Center for Genomics and Systems Biology, 12 Waverly Place Rm 621, New York, NY, 10003, US
2 - Fordham University, Biological Sciences, Larkin Hall Rm 350, 441 East Fordham Road, Bronx, NY, 10458, USA
3 - New York University, Biology, Center for Genomics and Systems Biology, 12 Waverly Place Rm 621, New York, NY, 10003, USA
4 - INVASIVE PLANT RESEARCH LAB, 441 E. Fordham Road, 160 Larkin Hall, Bronx, NY, 10458, United States

Keywords:
Natural Selection
Gene expression
Abiotic stress
evolution.

Presentation Type: Oral Paper
Session: MOL1, Molecular Ecology
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 12:30 PM
Number: MOL1001
Abstract ID:193
Candidate for Awards:None