Heading date is a critical agronomic trait that determines crop yield. Although numerous genes associated with heading date have been identified in rice, the mechanisms involving Small Auxin Up RNA (SAUR) family have not been elucidated. In this study, the biological function of several SAUR genes was initially investigated using the CRISPR-Cas9 technology in the Japonica cultivar Zhonghua11 (ZH11) background. Further analysis revealed that the loss-of-function of OsSAUR56 affected heading date in both NLD (natural long-day) and ASD (artificial short-day). OsSAUR56 exhibited predominant expression in the anther, with its protein localized in both the cytoplasm and nucleus. OsSAUR56 regulated flowering time and heading date by modulating the expression of the clock gene OsGI, as well as two repressors Ghd7 and DTH8. Furthermore, haplotype-phenotype association analysis revealed a strong correlation between OsSAUR56 and heading date, suggesting its role in selection during the domestication of rice. In summary, these findings highlights the importance of OsSAUR56 in the regulation of heading date for further potential facilitating genetic engineering for flowering time during rice breeding.

抽穗期是决定作物产量的关键农艺性状。尽管在水稻中已鉴定出许多与抽穗期相关的基因，但涉及小生长素上调 RNA (SAUR)家族的机制尚未阐明。本研究以粳稻品种中华11号（ZH11）为背景，利用CRISPR- Cas9技术初步研究了多个SAUR基因的生物学功能。进一步的分析表明， OsSAUR56的功能丧失影响了 NLD（自然长日照）和 ASD（人工短日照）的抽穗日期。OsSAUR56在花药中表现出主要表达，其蛋白定位于细胞质和细胞核中。OsSAUR56通过调节时钟基因OsGI以及两个阻遏蛋白Ghd7和DTH8的表达来调节开花时间和抽穗日期。此外，单倍型-表型关联分析揭示了OsSAUR56与抽穗日期之间的强相关性，表明其在水稻驯化过程中的选择中发挥作用。总之，这些发现强调了OsSAUR56在调节抽穗日期中的重要性，以进一步促进水稻育种过程中开花时间基因工程的潜力。