Systems Biology on Ecosystems: Exploring the Mechanism of Synchronized Flowering by Integrating Molecular and Modeling Approaches
The genetic basis of the evolutionary transition from outcrossing to selfing has been a major focus in evolutionary biology. Selfing, most commonly, evolved through the breakdown of the self-incompatibility (SI) system that consists of the male specificity component, the S-locus cysteine-rich protein (SCR), the female specificity component, the S-locus receptor kinase (SRK) and genes that involve in downstream signaling pathway. SRK, a transmembrane serine/threonine receptor kinase that expresses on the stigma, recognizes self-pollen when SCR, a ligand of SRK that expresses in the pollen coat, of the same haplotype interacts with it. Activation of SRK then triggers downstream cascade in stigma to inhibit pollen tube elongation and thus, preventing self-fertilization.
My PhD project focuses on the evolution of self-compatibility (SC) in Arabidopsis kamchatica. It is a selfing tetraploid species, originated through allopolyploidization of multiple individuals from two diploid species, Arabidopsis halleri and Arabidopsis lyrata that are predominantly outcrossing. Five SRK haplogroups have been identified in Arabidopsis kamchatica. Interpecific crosses with its parental species, Arabidopsis halleri showed that SRK and genes involved in downstream signaling pathway are still functional in some accessions, while no functional SCR has been identified. This suggests that mutation in the male component, SCR is responsible for the loss of SI in Arabidopsis kamchatica. However, the isolation of SCR through conventional PCR method has been difficult due to its short and highly polymorphic sequences. Therefore, next-generation sequencing has been exploited for the isolation of SCR. Functional and population genetic studies of the S-locus genes are essential to unveil the evolution of SC in Arabidopsis kamchatica.
Mot-clé: Self-incompatibility, Allotetraploid, Arabidopsis kamchaticaretourner