227T Poster - Population Genetics
Thursday June 09, 9:15 PM - 10:00 PM

Authors:
Sonal Gupta ¹; Zoe Joly-Lopez ²; Simon Groen ³; Steven Franks ⁴; Michael Purugganan ^1,5

Affiliations:
1) New York University, New York; 2) Université du Québec à Montréal, Quebec; 3) University of California, Riverside; 4) Fordham University, New York ; 5) New York University Abu Dhabi, Abu Dhabi, United Arab Emirates

Keywords:
Natural selection

Changes in gene expression is an important aspect of adaptation. Stressful environments can act as selective pressure leading to alterations in relative gene expression levels. Soil salinity is one of the most common stressful environments, especially for rice (Oryza sativa) in the arid and semi-arid regions. Here we assayed gene expression for a total of ~1200 individuals from 195 lines of rice exposed to control and salinity stress. Next, using phenotypic selection analysis we estimate the type and strength of selection on the levels of gene expression for over 18,000 transcripts. We found that in contrast to the control conditions, wherein majority of the transcripts are under (nearly) neutral selection or under weak stabilizing selection, the strength of selection increases under salinity stress. Moreover, we found that a higher proportion of transcripts are conditionally neutral (10%) than are antagonistically pleiotropic (0.378%) indicating a lack of trade-off at the expression levels. Interestingly, multivariate selection revealed pathways associated with amino-acid metabolism to be enriched under salinity stress suggesting a role of amino-acid metabolism in response to salinity, as has been suggested in other species. Additional work will provide insights into the molecular underpinnings of response to salinity stress in rice.