Abstract Blue light (BL) receptor phototropins (phots) regulate numerous BL-induced physiological responses through NPH3/RPT2-like (NRL) family members. However, how phots and NRL proteins regulate plant immunity remain incompletely understood. This study demonstrates that Stphot2 negatively regulated resistance against Phytophthora infestans , the causal agent of late blight, in potato and Nicotiana benthamiana . Stphot2 interacts with an NRL protein, StNRL-30, which functions as a susceptibility factor. Homodimerization and C-terminal consensus sequence (RxSΦS) of StNRL-30 are essential for accelerating P. infestans infection. The study identifies StNRL-30’s interaction with mitochondrial Peroxiredoxin-IIF (StPRXIIF), which positively regulates resistance against P. infestans . StPRXIIF overexpression upregulates mitochondrial alternative oxidase genes and salicylic acid pathway genes, while downregulating jasmonic acid pathway genes. StNRL-30 initiates StPRXIIF degradation, enhanced by Stphot2. In addition, BL treatment promotes StPRXIIF turnover and induces the translocation of the StNRL-30–StPRXIIF complex from the plasma membrane to the chloroplasts. These findings demonstrate how the BL receptor Stphot2, along with StNRL-30, modulates plant immunity by affecting the stability and localization of the positive immunoregulator StPRXIIF, providing insights into BL and plant immunity crosstalk.
Qiu et al. (2026) studied this question.