In eukaryotic organisms, meiosis is an essential part of sexual reproduction as it shuffles the parental genetic information and forms the basis for haploid spore formation. The level of genetic exchange between parental chromosomes in meiosis is tightly regulated and involves the orchestrated action of several ‘recombination’ proteins. Recent studies in yeast and metazoans have revealed an additional role for the environment. More specifically, abiotic stress conditions enhance the meiotic homologous recombination (MHR) frequency, providing an important mechanism to increase genetic variation and adaptation to adverse conditions. In plants, little is known about the influence of (a)biotic stress on MHR, however, preliminary studies suggest a similar stress-dependent regulatory mechanism. In the proposed project, we aim to characterize the effect of different stress factors on MHR and cell division in plants. To achieve this, we take advantage of the Arabidopsis quartet1 (qrt1) FTL tetrad analysis system, which enables simultaneous screening for alterations in MHR and cell division. To elucidate the underlying stress-responsive mechanism(s), both cytological and molecular approaches will be used to identify the meiosis-specific targets and to reveal stressresponsive signaling pathways involved. As such, the putative requirement of specific plant hormones will be tested and forward and reverse genetics will be used to identify related meiotic genes/proteins.