株高是影响糜子(Panicum miliaceum)抗倒伏和产量的关键农艺性状之一, 解析其调控机制对糜子遗传改良和高产育种具有重要意义。本研究通过多组学方法, 以高秆野生型糜子J08及其矮秆突变体AJ08为材料, 通过整合大田和盆栽环境下表型、转录组与植物激素数据, 筛选调控糜子株高的关键基因。试验结果表明, AJ08的株高与各节间长度均显著低于J08, 且J08的赤霉素(GA)含量是AJ08的1.9倍以上。转录组数据分析共筛选出7454个差异表达基因, 差异基因主要集中在植物激素信号转导、二萜类化合物生物合成等通路中。其中富集了GA合成和分解相关基因(KAO、GA2ox1、GA20ox1B)、信号转导基因(GAI、BKI1、XTH24)及生长素响应基因(SAUR32、GH3.8)。本研究推测AJ08的矮化表型主要由赤霉素合成关键基因KAO (C2845_PM13G01100)与GA20ox1B (C2845_PM02G40950)的下调所致。

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.