Abstract
BACKGROUND: Tiller angle, a key determinant of plant architecture in rice (Oryza sativa), critically influences photosynthetic efficiency and grain yield potential. Nevertheless, the molecular mechanisms that regulate tiller angle remain poorly characterized. As a central component of the ascorbate-glutathione cycle, ascorbate peroxidase (APX) scavenges reactive oxygen species (ROS) and maintains cellular redox homeostasis, thereby modulating diverse growth and developmental processes in plants. Despite its established pleiotropic functions, the specific role of OsAPX2 in controlling tiller angle in rice has yet to be elucidated. RESULTS: Here, we employed an integrated transcriptomic and metabolomics analyses to elucidate the role of OsAPX2 in regulating rice tiller angle. Comparative analysis revealed 1,473 differentially expressed genes (DEGs) in the apx2 mutant, with significant enrichment in 23 pathways including starch and sucrose metabolism, plant-pathogen interaction, and plant hormone signal transduction. Concurrently, OsAPX2 deletion perturbed the metabolome, leading to significant accumulation changes in 34 metabolites (15 increased, 19 decreased). Moreover, the results of co-expression analysis showed that the interactions of identified DEGs and DEMs diversely involved in starch and sucrose metabolism, pentose phosphate pathway, amino sugar and nucleotide sugar metabolism, indicating that OsAPX2 may be involved in the regulation of these processes during tillering stage. CONCLUSION: The results indicated that a loss-of-function mutation in OsAPX2 increased the tiller angle by (i) enhancement of the starch and sucrose metabolism, (ii) promotion of plant hormone signal transduction pathways. This study provided new mechanistic insight into how this pleiotropic regulator modulated carbohydrate metabolism and plant hormone signal transduction pathways that specifically link ROS signaling to tiller angle. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12864-026-12557-6.