Fang Pengpeng, Zhou Yi, Zhang Li, Zhang Wuhan, He Qiang, Lan Duo, Zeng Jia, Deng Huafeng, Shu Fu, Sun Pingyong
Longping Branch, College of Biology, Hunan University, Changsha, 410125, China.
State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China.
BMC Genomics. 2025 Jul 1;26(1):629. doi: 10.1186/s12864-025-11809-1.
Hybrid rice is pivotal for ensuring food security in China, yet challenges persist in its seed production. Sterile lines commonly face issues such as necking, gibberellins (GAs) are key regulators of panicle exsertion in rice, necessitating increased application of GAs during seed production, leading to elevated costs and environmental pollution. The novel photoperiod-thermosensitive genic male sterile line Shuang 1S addresses these limitations through its unique non-necked morphology and has super high yield of seed production.
To elucidate the regulatory pathways governing panicle exsertion and identify novel potential genes, this study assessed endogenous GA levels and performed RNA-seq analysis on two sterile lines, Shuang 1S and Han 2S, which displayed notable differences in panicle exsertion. Among 20 sterile lines examined, Shuang 1S demonstrated the highest panicle grains exsertion rate (91.03%) and the longest inverted first internode (28.24 cm). The findings revealed a 1.5-fold increase in GA content in Shuang 1S compared to Han 2S. Additionally, 2,147 up-regulated and 2,709 down-regulated genes were identified between SP (Shuang 1S) and HP (Han 2S), including 15 genes (10 up-regulated and 5 down-regulated) involved in GA biosynthesis and metabolism. KEGG enrichment analysis of the differentially expressed genes (DEGs) revealed significant enrichment in pathways including diterpenoid biosynthesis and plant hormone signal transduction, which are associated with gibberellic acid (GA) synthesis and catabolism.
We found that panicle exsertion was directly related to GAs content, and mainly enriched in diterpenoid biosynthesis, plant hormone signal transduction. These findings present new potential candidate genes for future investigations into the molecular mechanisms underlying the regulation of panicle exsertion in rice.
杂交水稻对保障中国粮食安全至关重要，但其制种仍面临挑战。不育系通常存在包颈等问题，赤霉素（GAs）是水稻穗抽出的关键调节因子，制种过程中需要增加GAs的施用量，这导致成本上升和环境污染。新型光温敏核不育系双1S通过其独特的不包颈形态解决了这些限制，并且具有超高的制种产量。
为阐明调控穗抽出的途径并鉴定新的潜在基因，本研究评估了两个不育系双1S和旱2S的内源GA水平，并进行了RNA测序分析，这两个不育系在穗抽出方面表现出显著差异。在所检测的20个不育系中，双1S表现出最高的穗粒抽出率（91.03%）和最长的倒一节间（28.24厘米）。研究结果显示，双1S中的GA含量比旱2S增加了1.5倍。此外，在SP（双1S）和HP（旱2S）之间鉴定出2147个上调基因和2709个下调基因，其中包括15个参与GA生物合成和代谢的基因（10个上调和5个下调）。对差异表达基因（DEGs）的KEGG富集分析表明，在包括二萜生物合成和植物激素信号转导等途径中显著富集，这些途径与赤霉素（GA）的合成和分解代谢相关。
我们发现穗抽出与GAs含量直接相关，主要富集在二萜生物合成、植物激素信号转导中。这些发现为未来研究水稻穗抽出调控的分子机制提供了新的潜在候选基因。
