The rice genome contains 13 Flowering Locus T-Like (FT-Like) genes, among which, OsFTL2/Hd3a and OsFTL3/RFT1 are characterized as florigen-encoding genes, promoting rice flowering under short-day and long-day conditions, respectively. However, the functions of the other FT-Like members are still unknown in rice. In this study, we characterized and identified a member of FT-Like family, OsFTL8 gene. The investigation of photoperiodic expression pattern showed that OsFTL8 transcription was mainly induced under short-day conditions. The qRT-PCR and GUS staining assays indicated that OsFTL8 was broadly expressed in various organs, including stems, leaves and panicles. OsFTL8 overexpression transgenic lines and its knockout mutants displayed no obvious change in their heading date, compared with the wild type. However, the pollen viability and seed setting rate were decreased in the overexpression transgenic lines. OsFTL8 localizes in both nucleus and cytoplasm. And we found that OsFTL8 does not interact with OsFD1 in vivo, suggesting that OsFTL8 may not be the component of florigen activation complex (FAC). In summary, our results indicate that OsFTL8 is associated with pollen viability and not involved in regulating rice flowering time, implying functional divergence of FT-Like members.

水稻基因组包含13个开花轨迹T-Like（FT-Like）基因，其中OsFTL2 / Hd3a和OsFTL3 / RFT1被表征为荧光素编码基因，分别促进了水稻在短日和长日条件下的开花。但是，其他类似FT成员的功能在水稻中仍然未知。在这项研究中，我们表征并鉴定了FT样家族OsFTL8基因的成员。光周期表达模式的研究表明，OsFTL8转录主要是在短期条件下诱导的。qRT-PCR和GUS染色检测表明OsFTL8在茎，叶和穗等各种器官中广泛表达。与野生型相比，OsFTL8过表达转基因品系及其敲除突变体的抽穗期无明显变化。然而，过表达转基因株系的花粉活力和结实率降低。OsFTL8定位在细胞核和细胞质中。并且我们发现OsFTL8在体内不与OsFD1相互作用，这表明OsFTL8可能不是荧光原激活复合物（FAC）的组成部分。总之，我们的结果表明OsFTL8与花粉生存能力相关，并且不参与调节水稻开花时间，这意味着FT-Like成员的功能存在差异。