Valsa mali effector Vm_04797 interacts with adaptor protein MdAP-2β to manipulate host autophagy.
Yubo SunDanyan LuoYuerong LiuWenyan TuRunmin CheHao FengLili HuangFengwang MaChanghai LiuPublished in: Plant physiology (2024)
Apple Valsa canker, caused by the ascomycete fungus Valsa mali, employs virulence effectors to disturb host immunity and poses a substantialthreat to the apple industry. However, our understanding of how V. mali effectors regulate host defense responses remains limited. Here, we identified the V. mali effector Vm_04797, which was up-regulated during the early infection stage. Vm_04797, a secreted protein, suppressed Inverted formin 1 (INF1)-triggered cell death in Nicotiana benthamiana and performed virulence functions inside plant cells. Vm_04797 deletion mutants showed substantiallyreduced virulence towards apple. The adaptor protein MdAP-2β positively regulated apple Valsa canker resistance and was targeted and degraded by Vm_04797 via the ubiquitination pathway. The in vitro analysis suggested that Vm_04797 possesses E3 ubiquitin ligase activity. Further analysis revealed that MdAP-2β is involved in autophagy by interacting with Malus domestica autophagy protein 16 MdATG16 and promoting its accumulation. By degrading MdAP-2β, Vm_04797 inhibited autophagic flux, thereby disrupting the defense response mediated by autophagy. Our findings provide insights into the molecular mechanisms employed by the effectors of E3 ubiquitin ligase activity in ascomycete fungi to regulate host immunity.
Keyphrases
- cell death
- cell cycle arrest
- endoplasmic reticulum stress
- pseudomonas aeruginosa
- escherichia coli
- signaling pathway
- type iii
- staphylococcus aureus
- oxidative stress
- induced apoptosis
- protein protein
- binding protein
- amino acid
- antimicrobial resistance
- biofilm formation
- transcription factor
- dendritic cells
- regulatory t cells
- small molecule
- immune response