Description du projet
En quête d’une fécondation préférentielle chez les plantes dotées de spermatozoïdes isomorphes
La reproduction des plantes à fleurs s’appuie sur un processus de fécondation double: un spermatozoïde fusionne avec l’ovule pour produire l’embryon et un autre fusionne avec la cellule centrale pour produire l’albumen nutritif. Chez la plupart des plantes à fleurs, les deux spermatozoïdes sont isomorphes (identiques). Chez certaines espèces dotées de spermatozoïdes dimorphes, un spermatozoïde peut fusionner en priorité avec l’ovule. On ignore toutefois si ce phénomène est aussi à l’œuvre chez les plantes dotées de spermatozoïdes isomorphes. Fort du soutien du programme Actions Marie-Skłodowska-Curie, le projet SAMEorNOT répondra à cette question ouverte en créant la première ligne de marqueurs unicellulaires de spermatozoïdes fondée sur les différences transcriptomiques entre deux spermatozoïdes isomorphes identifiées au moyen de l’analyse de séquences d’ARN en cellule unique.
Objectif
Human societies are sustained by flowering plants in different ways but especially as a key food supplier. However, it is known that increasing global temperatures strongly affect plant reproduction and the growing human population will require more food in short-middle term. Thus, to create new crop varieties more resistant to heat stress and with enhanced yield, a deeper understanding of the mechanism of plant sexual reproduction will be crucial for increasing the efficiency of plant breeding programs. Plant reproduction relies on a double fertilization process, in which two sperm cells from a pollen grain reach the ovule and one fertilize the egg cell while the other the central cell. In some species with dimorphic sperm cells a preferential fertilization of each sperm cell has been described, but for Arabidopsis thaliana as well as for many economically important crops with isomorphic sperm cells this question remains unclear. The main goal of this project is to identify by single cell RNA-seq analysis potential transcriptomic differences between the two Arabidopsis sperm cells. To do that, individual sperm cells from pollen tubes growing through female stylar transmitting tissue (semi in vivo) will be isolated by micromanipulation using a specially designed microfluidic chamber on an inverted microscope. The identification of differentially expressed genes would enable for the first time the creation of a sperm single-cell marker line to eventually explore a hypothetical preferential fertilization in Arabidopsis. These results can be adapted for plant breeding programs to develop impactful biotechnological tools, like haploid inducer lines with genetically modified sperm cells to specifically deliver components in the egg cell to induce in vivo gynogenesis. Additionally, the results will be a valuable scientific resource to address other topics beyond the preferential fertilization, like exploring hybridization barriers based on gamete recognition.
Champ scientifique
Programme(s)
- HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA) Main Programme
Régime de financement
MSCA-PF - MSCA-PFCoordinateur
1099 085 Lisboa
Portugal