P-171 - Understanding the cooperation of Myzus persicae effectors Mp1 and Mp58 during aphid infestation

Aphids are phloem-feeding insects that cause significant crop loss worldwide. Understanding molecular plant-aphid interactions is important for the development of new protection strategies. During infestation, aphids secrete effector molecules into host cells that associate with host proteins to disrupt or alter their function, but whether they work together is unknown. We previously identified a highly conserved effector pair that is genomically linked and under shared transcriptional control in several aphid species, suggesting that the encoded proteins may function together in promoting susceptibility. In the major agricultural pest Myzus persicae, this effector pair consists of Mp1 and Mp58. We have found that Mp1 and Mp58 interact and co-localise in Nicotiana benthamiana cells. In addition, we have identified that Mp58 shares a known target of Mp1, Vacuolar Protein Sorting Associated Protein 52 (VPS52). Using a series of VPS52 variants we found that Mp1 and Mp58 target different N-terminal regions of VPS52. While Mp1 associates with VPS52 at vesicle-like structures, Mp58 and VPS52 associate in the cytoplasm, suggesting distinct VPS52 targeting mechanisms. Using biochemistry and structural biology approaches along with functional characterisation assays we are exploring the role of effector complex formation in host susceptibility. Our work highlights potential effector cooperation, adding a novel layer of complexity in the molecular dialogue at the plant-aphid interface.