Fluctuating selection on migrant adaptive sodium transporter alleles in coastal Arabidopsis thaliana
Busoms, Silvia (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)
Paajanen, Pirita (John Innes Centre. Department of Cell and Developmental Biology)
Marburger, Sarah (John Innes Centre. Department of Cell and Developmental Biology)
Bray, Sian (John Innes Centre. Department of Cell and Developmental Biology)
Huang, Xin-Yuan (Nanjing Agricultural University. State Key Laboratory of Crop Genetics and Germplasm Enhancement)
Poschenrieder, Charlotte (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)
Yant, Levi (University of Nottingham. School of Life Sciences)
Salt, David (University of Nottingham. Division of Plant and Crop Sciences)

Data:	2018
Resum:	The natural landscape contains a highly heterogeneous array of environments that drive the adaptive differentiation of populations, including adaptation to elevated salinity. Our research emphasizes an integrated genetic, physiological, and ecological approach to understand the role of naturally evolved high-affinity K + transporter (HKT1;1) allelic variants in the adaptation of Arabidopsis thaliana populations to fluctuating salinity dynamics in nature. This information not only provides a case study fruitfully taking identification of natural variants through population demographic dynamics to molecular function but also is valuable for improving the sustainability of crop yields as the stress from salinity escalates due to increasing population pressures and global climate change. 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.
Ajuts:	European Commission 679056 Ministerio de Ciencia e Innovación BFU2013-42839-R Ministerio de Ciencia e Innovación BFU2016-75176-R European Commission 291798
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Saline adaptation ; HKT1 ; Fluctuating selection ; Population genetics ; Evolution
Publicat a:	Proceedings of the National Academy of Sciences of the United States of America, Vol. 115, Issue 52 (December 2018) , p. E12443-E12452, ISSN 1091-6490

DOI: 10.1073/pnas.1816964115
PMID: 30530653

10 p, 1.6 MB

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