Sexual selection in plants: testing for female cryptic choice and for the perception of the mating environment
(Marie Sklodowska-Curie2020-2021 with Prof. Mathilde Dufaÿ)
Pollen tubes interacting with pistil tissues
Increasing evidences suggest that sexual selection has played an important role in shaping plant reproductive strategies. However, we are especially ignorant of whether plants have evolved the ability to filter mating partners based on their pollen grain characteristics during the post-pollination phase of the life-cycle, resembling a female choice. It is equally unknown whether plants have evolved some ability to perceive their reproductive opportunities and plastically adjust their vegetative and reproductive morphologies as to maximize their chances to access mates. My Marie Curie project uses a multi-disciplinary approach combining experimental evolution, paternity analyses and physiological analyses to study aspects of plant perception and filtering of mating partners. My project aims at (1) quantifying the variation between females in their style physiology during the post-pollination phase and relate it with the number of mates and with the performance of pollen grains of their partners; (2) evaluating through experimental evolution both the evolution of style morphology and physiology linked to their ability to filter pollen grains and the evolution of pollen grain performance in situations of monoandry vs. polyandry and, (3) testing empirically whether plant-plant communication allows plants to perceive their mating opportunities and the genetic diversity of their mates and plastically adjust their reproductive strategy to maximize their chances to mate.
Sexual selection and sexual dimorphism in plants
(Post-doc in Prof. John Pannell’s group 2015-2019)
Experimental evolution of sexual dimorphism
Sexual selection is recognized in animals as a force promoting divergence of phenotypic characters between males and females. Male-male competition has been shown to trigger extreme cases of sexual dimorphism in many animal species. But, to what extant such male-male competition also explain the evolution of sexual dimorphism in dioecious plants is still poorly understood. Using experimental evolution, I am currently studying whether increased male-male competition can affect the evolution of the degree of sexual dimorphism in wind-pollinated plants. In the model herb species Mercurialis annua, I set up experimental populations grown each generation either at a low density or at a high density, thus varying the level of male-male competition. Plant height is supposed to enhance male competitive abilities by dispersing pollen from higher heights and could therefore be selected as a result of stronger competition for accessing sexual partners. I am also studying the evolution of protein expression in pollen coats thanks to proteomics to study selection on proteins involved in pollen adhesion and re-hydratation. Indeed, protein expression may be selected because of its impact on male gametophyte performance during pollen-pistil molecular interactions. Collaborators: John Pannell, Patrice David, Etienne Klein, Jean-Claude Mollet, Arnaud Lehner
Sex-specific requirements and sexual dimorphism in plants
(Post-doc in Prof. John Pannell’s group 2015-2019)
Dioecious herb Mercurialis annua
Most literature on the plant sexual system evolution consider the existence of one single resource limiting similarly all plant functions. However, several studies highlighted that ovule and fruit production are mostly limited by carbon while pollen production mostly requires nitrogen. Using optimal control theory, we are theoretically studying the optimal sex-specific resource allocation of both carbon and nitrogen and the effect of limitation in these currencies on sexual dimorphism evolution. Using Mercurialis annua as a model species, we also investigated sex-specific plastic responses to carbon limitation.
Collaborators: John Pannell, Mauricio Gonzalez-Forrero, Patrice David
Evolution of sex-specific selection gradients in a natural population of Leucadendron rubrum
(Post-doc with Dr. Ophelie Ronce and Prof. Agnès Mignot 2013-2014)
Dioecious perenial shrub Leucadendron rubrum
To further understand how male and female morphologies are shaped through natural, fecundity and sexual selection, it is critical to evaluate selection on male and female morphologies in natural populations using life-time estimation of fitness. In one of the most dimorphic wind-pollinated angiosperm species Leucadendron rubrum, we are quantifying the strength and direction of selection acting in male and female morphologies using molecular data combined with spatial data. We specifically developed a spatially explicit model to estimate jointly both pollen and seed dispersal kernels and the variance in reproductive success of males and females.
Jeanne Tonnabel 