Abstract: INTRODUCTION: Plant height is one of the key agronomic traits influencing lodging resistance and yield in Broomcorn millet (Panicum miliaceum). Elucidating its regulatory mechanism is of great significance for advancing genetic improvement and high-yield breeding in this crop.
RATIONALE: This study employed a multi-omics approach, utilizing the tall wild-type broomcorn millet J08 and its dwarf mutant AJ08. By integrating phenotypic data, transcriptomic profiles, and phytohormone levels from both field and pot environments, key genes involved in regulating plant height in broomcorn millet were screened.
RESULTS: The plant height and individual internode lengths of AJ08 were significantly lower than those of J08. The gibberellin (GA) content in J08 was more than 1.9 times higher than in AJ08. Transcriptome data analysis identified a total of 7, 454 differentially expressed genes, which were predominantly enriched in pathways such as plant hormone signal transduction and diterpenoid biosynthesis. Among these, genes related to GA synthesis and degradation (KAO, GA2ox1, GA20ox1B), signal transduction genes (GAI, BKI1, XTH24), and auxin-responsive genes (SAUR32, GH3.8) were notably enriched.
CONCLUSION: Based on the findings, it is inferred that the dwarf phenotype of AJ08 is primarily due to the downregulation of key gibberellin biosynthesis genes, specifically KAO (C2845_PM13G01100) and GA20ox1B (C2845_PM02G40950).

Identification of Key Candidate Genes for Plant Height in Broomcorn Millet Based on Transcriptome Data. As depicted, the dwarfism in mutant AJ08 is caused by the disruption of gibberellin metabolism through the coordinated deregulation of genes including KAO, GA2ox1, and GA20ox1, which inhibits DELLA protein degradation.

Key words: Plant height, Broomcorn millet, Hormones, RNA-Seq, Plant Signal Transduction