description
- Polyploids, which result from Whole Genome Duplication (WGD) events, are thought to have enhanced adaptability which might explain why they are so pervasive in nature and especially in crop plants. Furthermore, polyploids exhibit multiple advantages, from an agricultural perspective, such as often having larger fruits, and being more resilient to like drought and salinity. However, polyploidy requires evolving an adapted meiosis (well documented in natural polyploids) to cope with their additional chromosome sets during meiotic segregation; otherwise, resulting aneuploidies lead to genome instability and fertility problems. Because little is known about these adaptive mechanisms, the meiotic instability displayed by artificially generated (synthetic) polyploids (which lack of an evolved meiosis) cannot be eluded and the use of these synthetic polyploids remains exceptional as a tool to generate novel crop varieties. It is expected that regulating meiotic crossovers to prevent formation of multivalent associations among more than two homologous chromosomes during meiosis would decisively improve segregation and fertility of synthetic polyploids. While compelling, this hypothesis has not been formally tested. ProSPECT aims to address the problem of genome instability in synthetic polyploids by testing the viability of two strategies to artificially induce meiotic adjustments that might improve chromosome segregation using Arabidopsis thaliana polyploid mutants as a proof of concept. To do so I will use two strategies: (a) First, I will use meiotic recombination mutants known to reduce the number of meiotic crossovers to test if this is sufficient to limit the chances for multivalent formation in A. thaliana synthetic polyploid inbreds. (b) Second, I will use polyploid hybrids carrying combinations of meiotic mutants known to restrict meiotic crossovers to (nearly) identical partners to test if this is sufficient to impede associations among more than two chromosomes.