Mechanisms of meiotic restitution under heat: Arabidopsis thaliana as a model

The main objective of this research study is to assess the natural genetic variation in heat-induced meiotic restitution in the Arabidopsis thaliana germplasm, and exploit this to characterize underlying cytological mechanisms and to identify determining genetic factors. These insights will provide a fundamental basis for elucidating the molecular mechanisms that underpin heat sensitivity of meiotic cell division in plants. A preliminary study using a small set of Arabidopsis thaliana ecotypes has revealed significant variation in heat-induced meiotic restitution, indicating presence of natural genetic variation for this specific phenomenon in the Arabidopsis germplasm. This variation may be purely quantitative and attributed to different levels of penetrance of one single cellular defect, i.e. defected RMA biogenesis. However, it may also be conferred by various types of cellular defects with resulting 2n spores putatively having a different genetic make-up (FDR vs. SDR). A major goal within this project is hence to explore the natural genetic variation in male meiotic stability under heat in an extensive collection of Arabidopsis ecotypes to identify the cellular defects that underpin heat-induced meiotic restitution and to characterize the genetic make-up of resulting 2n pollen. This is highly relevant for plant genome evolution and may serve valuable for developing specific crop breeding applications. In addition, we also aim to identify the main genetic elementsthat underpin natural variation in heat-induced meiotic restitution in Arabidopsis and use this as a basis for further preliminary molecular studies to unravel regulatory mechanisms involved. As such, results of this project will contribute to our fundamental understanding of the molecular machinery that regulates the intricate process of meiotic cell division in plants and that mediates meiotic restitution and sexual polyploidization under heat stress.