Project
Thermal control of meiotic recombination
For adding novel beneficial traits to crop varieties, such as obtaining tolerance to abiotic and biotic stress, plant breeders select wild relatives with desired traits and cross breeding lines to introgress the traits via backcrosses. However, besides the desired new traits also many undesired traits may be inherited, especially in case the underlying genes are located on the same chromosome, leading to linkage drag.
Removing unwanted genes (alleles), while keeping desired target genes, requires a crossover (CO) between these genes which can occur during meiotic recombination, promoting the reshuffling of genes. However, some chromosomal regions hardly show any meiotic recombination (cold regions), which may result in a persistent linkage drag.
Fortunately, temperature has been shown to change crossover positions and frequency, likely by relaxing the histone protein packaging of DNA, resulting in opening up chromosomal regions for crossover recombination. In many plant species, including tomato and Arabidopsis, this appears to be regulated by both DNA and histone protein methylation. Therefore, temperature treatments provide new opportunity to unlock the accessibility of key traits for (pre)breeding. However, our understanding of the relationship between DNA methylation and histone methylation and its effect on recombination remains incomplete and requires further research to bridge the knowledge gap.
In this project, we will study the impact of temperature on the chromatin and DNA methylation dynamics with the potential to uncover the relationship between epigenetic modifications and CO position/frequency. We will use pollen profiling from F1 hybrids, a method that recently has been developed in our group, to determine the recombination landscape (position and frequency). Moreover, we will look for genetic variation with respect to the impact of temperature on the CO-landscape, search for genes underlying different meiotic recombination behaviour or have a stabilizing effect on meiotic recombination at elevated temperature. Candidate genes responsive to temperature and reprogramming of the recombination landscape will validated by means of CRISPR-Cas and RNAi. Although we will use tomato and Brassica’s as model species, there is a great potential to apply the obtained knowledge in other crops by making use of orthologs of the identified temperature responsive genes in this project.