《FT/TFL1基因家族调控高等植物生长发育的分子机理》
“2007 年的科学研究给人们以希望,世界各地先后有不同的科学家在不同的植物材料中证实 FT 蛋白就是人们苦苦寻找的“成花素”,它可以通过韧皮部从叶片运输到茎端分生组织,在茎端分生组织,FT 蛋白与 bZIP转录因子 FLOWERING LOCUS D (FD)互作,共同激活花分生组织基因 APETALA 1 (AP1)表达,从而促进成花转换并启动花发育过程(Abe et al., 2005; Notaguchi et al., 2008; Li et al., 2009)。TFL1 基因是FT/TFL1 基因家族的另一重要成员,其与 FT 基因的功能相反,抑制茎端分生组织形成花原基,延迟植物由营养生长向生殖生长的转变(Hanzawa et al., 2005)。这些研究成果为成花转换的研究带来新的转机,使得人们利用分子育种。”

《The TFL1 homologue KSN is a regulator of continuous flowering in rose and strawberry》
“In order to validate the function of RoKSN in continuous flowering control in roses, we studied vegetative mutant pairs showing different flowering behaviours. Frequently, CF roses mutate into climbing roses (Lewis, 1994). These climbing roses have primary shoots with indeterminate vegetative growth, whereas inflorescences are produced by axillary secondary shoots. They bloom in spring, and occasionally they can flower later in autumn (OR; Figure 1c). Only one mutation from OF to CF was described. An OF rose, i.e. ‘Félicité et Perpétue’ (FP), gave a CF dwarf mutant ‘Little White Pet’, LWP (Roberts et al., 1999). Each of the seven mutants studied showed a difference at the RoKSN locus when compared with the wild type. All six climbing mutants had a new allele at the RoKSN locus with a 1-kbp insertion at the same place as the 9-kpb insertion in the second intron (Figure 3). This 1-kbp sequence corresponded to the long terminal repeat (LTR) element of the retrotransposon. Five climbing mutants (‘Gold Bunny Cl.’, ‘Wendy Cusson Cl.’, ‘Pink Chiffon Cl.’, ‘Iceberg Cl.’ and ‘Peace Cl.’) had both the 9-kbp retrotransposon and 1-kbp LTR insertions. One climbing mutant (‘Old Blush Cl.’) only had the 1-kbp insertion (Figure 3). Mutation in climbing roses can be explained by the recombination of the retrotransposon in the climbing mutants. This recombination restores an active RoKSN allele (see discussion below). In the rare OF/CF mutation, FP was found to be heterozygous at the RoKSN locus (allele with and without the retrotransposon), whereas LWP only had the allele with the retrotransposon (Figure 3c). In LWP, by sequencing and Southern blot analyses, only one allele has been found, i.e. that with the retrotransposon (Figures 3c and S2). In this latter genotype, the absence of the active allele (without the retrotransposon) can be explained by the deletion of the allele or a somatic chromatid exchange. Analysis of these independent mutants demonstrated that recombination of the retrotransposon restored an OF phenotype, whereas deletion of the functional allele led to CF roses.
为了验证RoKSN在玫瑰连续开花控制中的功能,我们研究了表现出不同开花行为的营养突变对。通常,CF玫瑰会变异成攀援玫瑰(Lewis,1994)。这些攀援玫瑰的初级芽具有不确定的营养生长,而花序是由腋下次生芽产生的。它们在春天开花,偶尔可以在秋天晚些时候开花(或;图1c)。仅描述了从 OF 到 CF 的一个突变。一朵 OF 玫瑰,即“Félicité et Perpétue”(FP),给了 CF 侏儒突变体“小白宠物”,LWP(Roberts et al., 1999)。与野生型相比,研究的七个突变体中的每一个在RoKSN位点上都显示出差异。所有六个攀爬突变体在RoKSN位点都有一个新的等位基因,在第二个内含子中的1 kpb插入位置插入9 kbp(图3)。这个1 kbp序列对应于反转录转座子的长末端重复(LTR)元件。五个攀爬突变体(“Gold Bunny Cl.”,“Wendy Cusson Cl.”,“Pink Chiffon Cl.”,“Iceberg Cl.”和“Peace Cl.”)都有9 kbp反转录转座子和1 kbp LTR插入。一个攀爬突变体(“老腮红Cl.”)只有1 kbp插入(图3)。攀缘玫瑰的突变可以通过攀缘突变体中逆转录转座子的重组来解释。这种重组恢复了活跃的RoKSN等位基因(见下面的讨论)。在罕见的 OF/CF 突变中,发现 FP 在 RoKSN 位点(有和没有反转录转座子的等位基因)是杂合的,而 LWP 只有带有反转录转座子的等位基因(图 3c)。在LWP中,通过测序和南方印迹分析,仅发现一个等位基因,即具有反转录转座子的等位基因(图3c和S2)。在后一种基因型中,活性等位基因(没有反转录转座子)的缺失可以通过等位基因的缺失或体细胞染色单体交换来解释。对这些独立突变体的分析表明,逆转录转座子的重组恢复了OF表型,而功能性等位基因的缺失导致了CF玫瑰。”