LAUSR

Summary Direct control of protein level enables rapid and efficient analyses of gene functions in crops. Previously, we developed the RDDK‐Shield1 (Shld1) system in the model plant Arabidopsis thaliana for direct modulation of protein stabilization using a synthetic small molecule. However, it was unclear whether this system is applicable to economically important crops. In this study, we show that the RDDK‐Shld1 system enables rapid and tunable control of protein levels in rice and wheat. Accumulation of RDDK fusion proteins can be reversibly and spatio‐temporally controlled by the synthetic small‐molecule Shld1. Moreover, RDDK‐Bar and RDDK‐Pid3 fusions confer herbicide and rice blast resistance, respectively, in a Shld1‐dependent manner. Therefore, the RDDK‐Shld1 system provides a reversible and tunable technique for controlling protein functions and conditional expression of transgenes in crops.