"Plant-associated organisms secrete molecules to attenuate plant defence signalling and enable colonization of plant tissue. In contrast to bacterial plant pathogens, only a few oomycete effectors have been characterized. Many oomycete effectors carry a signal peptide and RxLR motif, and act inside host cells to suppress immunity. However, the mechanisms by which these effectors act remain to be elucidated. Jones’ laboratory study candidate effector genes mined from the genome sequence of Arabidopsis downy mildew (Hyaloperonospora arabidopsidis -Hpa) in high-throughput screens and discovered RxLR effectors which enhance/decrease virulence. The present project proposes to analyse in planta, the modes of action of ten promising RxLR effectors from Hpa that confer enhanced/decreased virulence. From these ten promising Hpa candidate effectors, I aim to select as soon as possible the three best candidates to perform in planta functional analysis. In this framework, the main objectives are the subcellular localisation of Hpa effectors in the host cell and the identification of Hpa effector plant targets. The characterization of oomycete effectors that enter the plant cell, their functions and protein-uptake mechanisms will be a fascinating area for understanding the basis of plant pathogenesis and will shed light on fundamental cellular mechanisms in plants, thus enhancing our understanding of plant signalling, metabolism, and cell biology."