Wakunaga Pharmaceutical Co., Ltd. 1624 Shimokodachi, Akitakatashi, Hiroshima 739-1195, Japan.
Plant J. 2012 Jan;69(1):116-25. doi: 10.1111/j.1365-313X.2011.04776.x. Epub 2011 Oct 25.
Flowering is a key event in plant life, and is finely tuned by environmental and endogenous signals to adapt to different environments. In horticulture, continuous flowering (CF) is a popular trait introduced in a wide range of cultivated varieties. It played an essential role in the tremendous success of modern roses and woodland strawberries in gardens. CF genotypes flower during all favourable seasons, whereas once-flowering (OF) genotypes only flower in spring. Here we show that in rose and strawberry continuous flowering is controlled by orthologous genes of the TERMINAL FLOWER 1 (TFL1) family. In rose, six independent pairs of CF/OF mutants differ in the presence of a retrotransposon in the second intron of the TFL1 homologue. Because of an insertion of the retrotransposon, transcription of the gene is blocked in CF roses and the absence of the floral repressor provokes continuous blooming. In OF-climbing mutants, the retrotransposon has recombined to give an allele bearing only the long terminal repeat element, thus restoring a functional allele. In OF roses, seasonal regulation of the TFL1 homologue may explain the seasonal flowering, with low expression in spring to allow the first bloom. In woodland strawberry, Fragaria vesca, a 2-bp deletion in the coding region of the TFL1 homologue introduces a frame shift and is responsible for CF behaviour. A diversity analysis has revealed that this deletion is always associated with the CF phenotype. Our results demonstrate a new role of TFL1 in perennial plants in maintaining vegetative growth and modifying flowering seasonality.
开花是植物生活中的一个关键事件，通过环境和内源性信号的精细调节，以适应不同的环境。在园艺学中，连续开花（CF）是一种广泛引入栽培品种的流行特性。它在现代玫瑰和林地草莓在花园中的巨大成功中发挥了重要作用。CF 基因型在所有适宜的季节开花，而一次性开花（OF）基因型仅在春季开花。在这里，我们表明在玫瑰和草莓中，连续开花受 TFL1 家族同源基因的控制。在玫瑰中，六个独立的 CF/OF 突变体在 TFL1 同源物的第二个内含子中存在反转录转座子的存在上有所不同。由于反转录转座子的插入，CF 玫瑰中基因的转录被阻断，并且缺少花抑制物会引发连续开花。在 OF-攀缘突变体中，反转录转座子发生重组，产生仅携带长末端重复元件的等位基因，从而恢复功能等位基因。在 OF 玫瑰中，TFL1 同源物的季节性调控可能解释了季节性开花，春季表达水平低，以允许第一次开花。在林地草莓（ Fragaria vesca ）中，TFL1 同源物编码区的 2-bp 缺失导致移码，并导致 CF 行为。多样性分析表明，这种缺失总是与 CF 表型相关。我们的研究结果表明 TFL1 在多年生植物中具有维持营养生长和修饰开花季节性的新作用。
