Genetics of natural variation and environmental modulation of immune-.Related hybrid incompatibilities in arabidopsis
- Autores: Kostadin Evgeniev Atanasov
- Directores de la Tesis: Antonio Fernández Tiburcio (dir. tes.), Ruben Alcazar Hernandez (codir. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2019
- Idioma: español
- Tribunal Calificador de la Tesis: Teresa Altabella Artigas (presid.), Jaime F. Martínez García (secret.), Blanca San Segundo de los Mozos (voc.)
- Programa de doctorado: Programa de Doctorado en Biotecnología por la Universidad de Barcelona
- Materias:
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- Resumen
Arabidopsis thaliana is a small ruderal weed with prominent north-hemisphere distribution. It has an autogamous style of reproduction, whereas about 3% of the natural population can exhibit outcrosses. Some of these outcrosses produce incompatible hybrids exhibiting temperature-dependent autoimmunity. The hybridization between accessions Ler (from North-Europe) and Kas-2 (from Central Asia) produces an incompatible hybrid. The genetics underlying the incompatibility is caused by the deleterious epistasic interactions between a unique Ler haplotype of RPP1-like genes and the SRF3 Kas-2 receptor-like kinase. The incompatibility exhibits recessive mendelian inheritance pattern and hybrids display strong dwarfism, spontaneous cell death, and sterility at 14 ◦C – 16 ◦C. By using EMS mutagenesis and CRISPR/Cas-9 gene editing on Ler/Kas-2 NIL plants, 15 RPP1-like intragenic loss-of-function mutations were identified. Furthermore, the impact of suppression of incompatibility was investigated in terms of disease resistance against hemibiotrophic or biotrophic pathogens. Moreover, changes on the global transcriptome and metabolite profiling were studied. The contribution of individual RPP1-like genes for the recognition of a local Hpa isolate (Gw) was carried out by cloning ATR1 effector and performing transient expression assays in tobacco plants. The environmental modulation of autoimmunity was studied with a focus on the nitrogen-based mineral nutrition. We found that increasing ammonium was sufficient to suppress the incompatibility and the mechanism behind implies signaling through nitric oxide and the contribution of the systemic acquired response master gene, NPR1. Furthermore, we suggest that ammonium enriched media has an impact on resistance to Pst turning the enhanced resistance on incompatible hybrids down to the parental lines. Finally, we investigated the natural variation to the plant herbicide, guazatine, on a set of 107 accessions. We found an association for the chlorophyllase 1 gene which was selected for functional validation together with the paralog chlorophyllase 2 gene. Chlorophyllase individual mutants and double mutants exhibit increased tolerance to guazatine. No geographical pattern between the tolerant genotype and gene phylogeny was found, whereas high proportion of tolerant accessions was detected in populations for Germany.
