Fluctuating selection on migrant adaptive sodium transporter alleles in coastal Arabidopsis thaliana
Year: 2018
Type: article
Abstract: Stressors such as soil salinity and dehydration are major constraints on plant growth, causing worldwide crop losses. Compounding these insults, increasing climate volatility requires adaptation to fluctuating conditions. Salinity stress responses are relatively well understood in Arabidopsis thaliana , making this system suited for the rapid molecular dissection of evolutionary mechanisms. In a large-scale genomic analysis of Catalonian A. thaliana , we resequenced 77 individuals from multiple salinity gradients along the coast and integrated these data with 1,135 worldwide A. thaliana genomes for a detailed understanding of the demographic and evolutionary dynamics of naturally evolved salinity tolerance. This revealed that Catalonian varieties adapted to highly fluctuating soil salinity are not Iberian relicts but instead have immigrated to this region more recently. De novo genome assembly of three allelic variants of the high-affinity K + transporter ( HKT1;1 ) locus resolved structural variation between functionally distinct alleles undergoing fluctuating selection in response to seasonal changes in soil salinity. Plants harboring alleles responsible for low root expression of HKT1;1 and consequently high leaf sodium ( HKT1;1 HLS ) were migrants that have moved specifically into areas where soil sodium levels fluctuate widely due to geography and rainfall variation. We demonstrate that the proportion of plants harboring HKT1;1 HLS alleles correlates with soil sodium level over time, HKT1;1 HLS -harboring plants are better adapted to intermediate levels of salinity, and the HKT1;1 HLS allele clusters with high-sodium accumulator accessions worldwide. Together, our evidence suggests that HKT1;1 is under fluctuating selection in response to climate volatility and is a worldwide determinant in adaptation to saline conditions.
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: hybrid
Awards: Genomic hotspots of adaptation to whole genome duplication, G1399071765, G1998039391, Genome-wide association mapping and landscape scale modelling of heritable ionomic diversity in Arabidopsis thaliana populations, The Genetic Basis and Adaptive Significance of Natural Ionomic Variation, Sources and Protracted Effects of Early Life Exposure to Arsenic and Mercury, G3306153304, G3919724847, Using genome diversity and evolution in natural outcrossing populations to understand adaptation and meet global challenges, Genome and Epigenome, G6791190511, The Genetic basis of Natural Ionomic Variation, Phenotypic Plasticity in Response to Environmental Challenges, G9000080583, G9000183997
OpenAlex ID: W2904471369