OsDPE2 Regulates Rice Panicle Morphogenesis by Modulating the Content of Starch

Starch is a carbon sink for most plants, and its biological role changes with response to the environment and during plant development. Disproportionating Enzyme 2 (DPE2) is a 4-α-glycosyltransferase involved in starch degradation in plants at night. LAX1 plays a vital role in axillary meristem initiation in rice. Herein, results showed that Oryza sativa Disproportionating Enzyme 2 (OsDPE2) could rescue the mutant phenotype of lax1-6, LAX1 mutant. OsDPE2 encodes rice DPE2 located in the cytoplasm. In this study, OsDPE2 affected the vegetative plant development of rice via DPE2 enzyme. Additionally, OsDPE2 regulated the reproductive plant development of rice by modulating starch content in young panicles. Furthermore, haplotype OsDPE2(AQ) with higher DPE2 enzyme activity increased the panicle yield of rice. In summary, OsDPE2 can regulate vegetative and reproductive plant development of rice by modulating starch content. Furthermore, DPE2 activities of OsDPE2 haplotypes are associated with the panicle yield of rice. This study provides guidance for rice breeding to improve panicle yield traits.