A SABRE family protein DITA1 regulates plant height and tiller angle in rice

Rice plant architecture is shaped by complex agronomic traits, such as plant height and tiller angle, which collectively determine yield potential. Although SABRE family proteins are conserved across eukaryotes, their roles in regulating plant architecture remain poorly understood. Here, we characterize the rice dwarf and increased tiller angle1 (dita1) mutant, which exhibits reduced plant height and spreading tillers due to abnormal cell morphology. Physiological analyses reveal that the dita1 mutant displays attenuated gravitropic responses, disrupted cytoskeletal organization, and impaired amyloplast sedimentation. DITA1 encodes a rice SABRE family member that likely localizes to the endoplasmic reticulum. Expression profiling shows that DITA1 is upregulated following gravistimulation and enriched at the tiller base during the tillering stage. Mutation in DITA1 alters the transcript levels of genes involved in auxin biosynthesis and asymmetric distribution. Furthermore, analysis of natural variation within the DITA1 coding region identifies associations between haplotypes and tiller angles. Collectively, our findings suggest that DITA1 contributes to the regulation of plant architecture through potentially influencing cytoskeletal dynamics, statolith-mediated gravitropism, and asymmetric auxin distribution, providing a genetic target for optimizing plant architecture in breeding programs.