Shaobo Wei, Long Cheng, Hongge Qian, Xia Li, Lianguang Shang, Yujie Zhou, Xiangyuan Ye, Yupeng Zhou, Yuan Gao, Lin Cheng, Chen Xie, Qingwen Yang, Qian Qian, Wenbin Zhou

Journal of Integrative Plant Biology; 2025; IF 9.30

DOI:10.1111/jipb.13856

Abstract

Flowering time is a critical agronomic trait in rice,directly influencing grain yield and adaptability tospecific planting regions and seasons. Florigens,including FLOWERING LOCUS T (FT) proteins Hd3a(OsFTL2) and RFT1 (OsFTL3), play central roles intransmitting flowering signals through rice's pho-toperiod regulatory network. While Hd3a and RFT1have been extensively studied, the functions andinteractions of other FT‐like proteins remain un-clear, limiting advancements in breeding strategiesfor early‐maturing rice varieties. Here, we demon-strate that the florigen‐like protein OsFTL1 forms aflorigen activation complex (FAC) and promotesflowering under both short‐day and long‐day conditions. OsFTL1 localizes to the nucleus and cyto-plasm, with predominant expression in the shootbase, facilitating its mobilization to the shoot apicalmeristem (SAM) to initiate flowering. Over-expression of OsFTL1 (OsFTL1‐OE) in leaves orshoot bases significantly accelerates flowering andalters plant architecture. In the nucleus, OsFTL1interacts with GF14c and OsFD1 to form an FAC,activating OsMADS14 and OsMADS15 expressionto drive flowering. Markedly, OsFTL1‐OE plantsdeficient in Hd3a and RFT1 exhibited earlier flow-ering compared with wild‐type plants, indicatingthat OsFTL1 can independently promote flowering.Furthermore, haplotype analysis identified OsFTL1‐Hap3, a beneficial variant associated with earlyflowering and comparable grain yields. These findings revealed that OsFTL1 can substitute for Hd3aand RFT1 in FAC formation, promoting floweringacross photoperiods, and highlighting its potentialapplication in breeding early‐maturing, high‐yieldrice varieties suitable for diverse environments.