The Puccinia striiformis effector Pst11215 manipulates mitochondria to suppress host immunity by promoting TaVDIP1-mediated ubiquitination of TaVDAC1.

Abstract

Mitochondria-induced cell death is closely correlated with plant immune responses against pathogens. However, the molecular mechanisms by which pathogens manipulate mitochondria to suppress host resistance remain poorly understood. In this study, a haustorium-specific effector Pst11215 from the wheat stripe rust pathogen Puccinia striiformis f. sp. tritici (Pst) was characterized by host-induced gene silencing. The interaction partners regulated by Pst11215 were screened using the yeast two-hybrid system. In addition, Pst11215-mediated immune regulation modes were further determined. The results showed that Pst11215 was required for Pst virulence. Pst11215 interacted with the wheat voltage-dependent anion channel TaVDAC1, the negative regulator of wheat resistance to stripe rust, in mitochondria. Furthermore, the E3 ubiquitin ligase TaVDIP1 targeted and ubiquitinated TaVDAC1, which can be promoted by Pst11215. TaVDIP1 conferred enhanced wheat susceptibility to Pst by cooperating with TaVDAC1. Overexpression of TaVDIP1 reduced reactive oxygen species (ROS) accumulation and abnormal mitochondria. Our study revealed that Pst11215 functions as an important pathogenicity factor secreted to the host mitochondria to compromise wheat resistance to Pst possibly by facilitating TaVDIP1-mediated ubiquitination of TaVDAC1, thereby protecting mitochondria from ROS-induced impairment. This research unveils a novel regulation mode of effectors hijacking host mitochondria to contribute to pathogen infection.