Wuhan Institute of Landscape Architecture, Wuhan, 430081, Hubei, China.
Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
Plant Cell Rep. 2023 Jun;42(6):1071-1088. doi: 10.1007/s00299-023-03014-9. Epub 2023 Apr 6.
TFL1-like genes of the basal eudicot Platanus acerifolia have conserved roles in maintaining vegetative growth and inhibiting flowering, but may act through distinct regulatory mechanism. Three TERMINAL FLOWER 1 (TFL1)-like genes were isolated and characterized from London plane tree (Platanus acerifolia). All genes have conserved genomic organization and characteristic of the phosphatidylethanolamine-binding protein (PEBP) family. Sequence alignment and phylogenetic analysis indicated that two genes belong to the TFL1 clade, designated as PlacTFL1a and PlacTFL1b, while another one was grouped in the BFT clade, named as PlacBFT. qRT-PCR analysis showed that all three genes primarily expressed in vegetative phase, but the expression of PlacTFL1a was much higher and wider than that of PlacTFL1b, with the latter only detected at relatively low expression levels in apical and lateral buds in April. PlacBFT was mainly expressed in young stems of adult trees followed by juvenile tissues. Ectopic expression of any TFL1-like gene in Arabidopsis showed phenotypes of delayed or repressed flowering. Furthermore, overexpression of PlacTFL1a gene in petunia also resulted in extremely delayed flowering. In non-flowering 35:PlacTFL1a transgenic petunia plants, the FT-like gene (PhFT) gene was significantly upregulated and AP1 homologues PFG, FBP26 and FBP29 were significantly down-regulated in leaves. Yeast two-hybrid analysis indicated that only weak interactions were detected between PlacTFL1a and PlacFDL, and PlacTFL1a showed no interaction with PhFDL1/2. These results indicated that the TFL1-like genes of Platanus have conserved roles in repressing flowering, but probably via a distinct regulatory mechanism.
伦敦悬铃木（Platanus acerifolia）TFL1 样基因在维持营养生长和抑制开花方面具有保守作用，但可能通过不同的调控机制发挥作用。从伦敦悬铃木中分离并鉴定了三个 TERMINAL FLOWER 1（TFL1）样基因。所有基因都具有保守的基因组组织和磷脂酰乙醇胺结合蛋白（PEBP）家族的特征。序列比对和系统发育分析表明，两个基因属于 TFL1 分支，分别命名为 PlacTFL1a 和 PlacTFL1b，而另一个基因则属于 BFT 分支，命名为 PlacBFT。qRT-PCR 分析表明，这三个基因主要在营养期表达，但 PlacTFL1a 的表达水平远高于 PlacTFL1b，后者仅在 4 月的顶芽和侧芽中以相对较低的水平检测到。PlacBFT 主要在成年树的幼茎中表达，其次是幼嫩组织。任何 TFL1 样基因在拟南芥中的异位表达均表现出开花延迟或抑制的表型。此外，PlacTFL1a 基因在矮牵牛中的过表达也导致开花极其延迟。在非开花的 35:PlacTFL1a 转基因矮牵牛植物中，FT 样基因（PhFT）显著上调，AP1 同源物 PFG、FBP26 和 FBP29 在叶片中显著下调。酵母双杂交分析表明，仅检测到 PlacTFL1a 与 PlacFDL 之间的弱相互作用，而 PlacTFL1a 与 PhFDL1/2 之间没有相互作用。这些结果表明，悬铃木的 TFL1 样基因在抑制开花方面具有保守作用，但可能通过不同的调控机制。
