The OsLHY-OsSCL30/OsDHT1 regulatory cascade coordinates heading date and plant height through Pre-mRNA splicing...

Heading date and plant height are critical agronomic traits in rice, governing climate adaptation and yield. Pre-mRNA splicing is a key post-transcriptional regulatory mechanism influencing plant development and adaptation. While splicing is implicated in regulating these traits, the roles of specific spliceosomal components and their target genes remain elusive.

This study aimed to identify and characterize novel splicing factors regulating heading date and plant height in rice, focusing on elucidating the molecular mechanisms involving the spliceosome and its downstream pathways.

We employed molecular genetics, protein interaction assays (e.g., yeast two-hybrid, bimolecular fluorescence complementation assay), the binding assays of transcript factor to cis-element (e.g., yeast one-hybrid, dual-luciferase reporter assay and electrophoretic mobility shift assay), gene expression analysis and splicing efficiency assays (qRT-PCR, RNA immunoprecipitation), and phenotypic and biochemist evaluation of transgenic rice lines (overexpression, gene-editing mutants).

We identifiedOsSCL30, a rice SR-like splicing factor. Its expression isdirectly activated by the circadian clock regulatorOsLHY, which binds theOsSCL30promoter. OsSCL30 interacts withDHT1to form spliceosomal components. This complex modulates splicing efficiency for specific target genes. OsSCL30 actspleiotropically: it delays heading date primarily via theGhd7-Ehd1-Hd3a/RFT1 pathway and reduces plant height throughpotential role in strigolactone signaling pathway. Importantly,OsLHY and OsSCL30 form a transcriptional-splicing feedback loop, suggesting a mechanism for maintaining homeostasis.

OsSCL30 functions as a core spliceosomal component, partnering with DHT1, to coordinately regulate rice heading date and plant height. This work uncovers a novel OsLHY-OsSCL30-DHT1 regulatory module integrating transcriptional control and pre-mRNA splicing. Our findings provide asignificant theoretical foundation and deliver valuablegermplasm resourcesfor enhancing rice adaptation and genetic breeding programs.