Self-incompatibility in plants

 

Self-incompatibility (SI) prevents self-pollination and limits inbreeding depression in flowering plants. Since SI is present in at least 50% of Angiosperm families, it is believed to have a profound impact on the evolution of flowering plants, with possible demographical repercussions for threatened populations. 

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I have investigated the effect of the interactions between SI, historical and demographical processes on the population dynamics of two plant species in contrasting ecologies.

In Arabidopsis halleri, I used simulated and empirical population genetics, coupled with phenotypic screening, to investigate the effect of outcrossing and negative frequency-dependent selection induced by SI on population structure and survival across different regimes of selection, migration and dispersion.

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By investigating the molecular causes for SI in Biscutella neustriaca, I brought a new model taxa for the study of SI evolution in Brassicaceae. In this micro-endemic plant species, I provided the first experimental evidence that, given certain conditions of local density and low genetic diversity, SI could affect population outcomes as a result of decreasing reproductive success. 

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With the collaboration of conservationists, we conducted an unprecedented sampling campaign in the Seine valley to study the demographic status and genetic diversity of B. neustriaca in a natural setting. This offered insights into the historic, demographic and anthropic events that shaped these populations and will be useful for conservation efforts while serving as primary material for future scientific studies.

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This work highlighted the demographic impact of SI on threatened plant populations and the importance to consider this reproduction system when managing these populations in fragile and fragmented landscapes.

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Link: Unité EEP - Université de Lille (France)