*3.7. Subcellular Localization of OsCAF1*

We cloned the coding sequence of *OsCAF1,* and the PCR product was fused to the N-terminus of the green fluorescent protein (GFP) in the pAN580 vector. Both the OsCAF1–GFP fusion construct and the empty GFP vector were transformed into rice protoplasts as previously described [35]. Protoplasts with GFP signals were observed under a laser scanning confocal microscope (Zeiss LSM700, Germany). The PCR amplification primers are listed in Supplementary Table S1.

#### *3.8. Yeast Two-hybrid Analysis*

The coding sequences of *OsCAF1* and *OsCRS2* (*Os01g0132800*) were amplified using gene-specific primers. Full-length *OsCAF1* and partial-length *OsCAF1* were cloned into pGBKT7 (BD) to generate the BD-OsCAF1, BD-OsCAF1-N, BD-OsCAF1-M, BD-OsCAF1-C, BD-OsCAF1-C1, BD-OsCAF1-C2, BD-OsCAF1-C3, and BD-OsCAF1-C4 plasmids. In addition, full-length OsCRS2 was cloned into pGADT7 (AD) to generate the AD-OsCRS2 plasmid. The pairwise plasmid was co-transformed into the AH109 yeast strain and growth on SD-T/L in a 28 ◦C incubator. Next, the co-transformed yeast strains were transferred to SD-T/L/H/A for interaction analysis.
