Characterisation of the epistatic hybrid incompatibility locus STRUBBELIG RECEPTOR FAMILY 3 in Arabidopsis

Sammanfattning: Populations of Arabidopsis thaliana have spread throughout temperate zones of the world and adapted to prevailing biotic and abiotic stress factors. Diverging popula-tions of Arabidopsis accessions can evolve postzygotic hybrid incompatibility (HI). In some cases, HI is caused by incompatible epistatic interactions between genes that have functionally diverged between- and within species. Crosses between the Euro-pean Landsberg erecta (Ler) and many central Asian accessions, like Kashmir-2 (Kas-2) and Kondara (Kond) suffers from it. Genetic analysis of this incompatibility has revealed its basis in a polymorphic cluster of Toll/interleukin-1 receptor-nucleo-tide binding-leucine rich repeat (TNL) RPP1 (Recognition of Peronospora parasitica 1)-like genes in Ler and alleles of the receptor-like kinase Strubbelig Receptor Fam-ily 3 (SRF3) in ecotypes Kas-2 and Kond, causing autoactivation of the plant innate immunity response. In this project I have analysed: I) the genetic variability of SRF3 in a segregating population of Ler relatives originally from Gorsów (Poland) and II) the molecular function of SRF3. My analysis showed that SRF3 might be more con-served in the Gorsow population compared to the Kas-2 and Kond accessions alt-hough it does not provide insight in the evolution of incompatibility. Analysis of the role of SRF3 using overexpressing and mutant lines and in silico prediction indicates that it might be involved in both drought and salt stress. In summary, this project sheds light into the role of SRF3 as a stress-related gene and its implication in hybrid incompatibility.