Researchers Discover Two Rice Proteins That Negatively Modulate Immunity

The Crop Journal highlights the significance of post-translational modifications (PTMs) in regulating rice plant immunity. Through a study conducted by China's Zhejiang University researchers and colleagues, two proteins were found to be vital in the defense response.

The researchers focused on the balance between two opposing PTMs, ubiquitination and SUMOylation, which control two proteins, OsEHD1 and OsEHD2, that act as negative regulators of rice defense against rice blast and bacterial blight. They found that the enzyme OsBBI1 tags OsEHD1 and OsEHD2 with a "destroy" signal (ubiquitin), marking them for degradation. Removing these two proteins led to improved rice plant immunity, confirming their function in weakening the defense response.

For the SUMOylation regulation, specific SUMO proteins tag OsEHD1 and OsEHD2 with a "protect" signal, stabilizing them and allowing them to suppress immunity. OsBBI1 was found to counteract this protective SUMOylation, restoring the plant's robust immune response by destroying the negative regulators.

The study reveals a molecular switch that fine-tunes OsBBI1-mediated destruction and SUMO-mediated protection of OsEHD1 and OsEHD2, thereby determining the strength of rice immunity and providing a key insight for breeding disease-resistant rice.

Read the research article from The Crop Journal.