Biology subjects

Bleau, J. R.

Publications and source records attributed to Bleau, J. R..

2 recordsLinked to original sources

bioRxiv2026

An aphid effector pair forms a hetero-oligomeric complex important for protein stability and activity

During disease and infestation, pathogens and pests deliver effectors inside their host to manipulate host responses, leading to immune suppression and altered nutrient availability. To be successful, pathogens and pests can produce and secrete large repertoires of effectors, consisting of up to hundreds of proteins. While effector virulence activities are usually studied in isolation, effectors can function together or cooperate to regulate transport and/or activity. An important example is the suppression of effector avirulence activity by plant pathogenic microbe effectors. Moreover, some effectors can physically associate with target host proteins and promote virulence. Here we explored the interaction of a conserved and co-regulated effector pair in aphids. Using a combination of computational modelling and crystallography combined with functional assays, we reveal a novel type of oligomeric assembly of the paired aphid effectors in a hexameric/octameric complex. Our data indicate that different oligomerization states exist among orthologs of this effector complex, suggesting that dynamic dissociation or subunit exchange may occur. Structure-based mutagenesis revealed that complex formation is essential for both effector protein stability and the in planta activity of one of these proteins. These findings emphasize the significance of effector hetero-oligomerization at the plant-insect interface, consistent with the model that this effector pair is an evolutionarily conserved module across aphid species.

biochemistry↗

bioRxiv2025

The highly conserved aphid effector pair Mp1-Mp58 associates to form an effector complex that targets host trafficking protein VPS52

Pathogen and pest effectors play a crucial role in manipulating plant biological processes, facilitating infection and infestation. While pathogens and pests secrete repertoires of effectors into their host plants, most effector function studies focus on characterising individual proteins. We previously identified a genetically linked and co-regulated gene pair in the aphid Myzus persicae encoding effectors Mp1 and Mp58. Here, we explored the functional link between these effectors. We used ectopic expression assays in Nicotiana benthamiana followed by co-immunoprecipitation assays and confocal microscopy to explore effector-effector and effector-target interactions and their subcellular localisation. We produced recombinant proteins to validate effector interactions and used computational modelling to predict effector complex 3D structures. We revealed that effectors Mp1 and Mp58 interact in planta and in vitro and likely form an oligomeric complex. Both effectors associate with the host target Vacuolar Protein Sorting associated Protein 52 (VPS52) to form an Mp1-Mp58-VPS52 complex which localises at vesicle-like structures. Our findings point to effector complex formation in plant-insect interactions and highlight a further layer of complexity in the molecular dialogue between plants and insects. Our work also shows the importance of considering the context in which effectors may function within a larger effector repertoire.

plant biology↗