Transcriptome analysis of Ghd7 promoter deletion lines in rice

The Ghd7 (Grain number, plant height, and heading date 7) gene integrates red light signals and circadian rhythms to regulate flowering time under long-day conditions in rice. To investigate the cis-regulatory mechanisms governing Ghd7 transcription, we generated a series of CRISPR/Cas9-mediated deletion mutants covering a 65 kb upstream genomic region. Through systematic deletion analysis, we identified a key regulatory region located between -26 kb and -30 kb from the transcription start site (TSS) of Ghd7, which is essential for its induction in response to morning light. Further refinement revealed that a 228 bp segment within this region plays a critical role in Ghd7 expression. These findings provide insights into the transcriptional regulation of Ghd7 and its role in light-mediated flowering control in rice.