Sheldon Candice C, Hills Melissa J, Lister Clare, Dean Caroline, Dennis Elizabeth S, Peacock W James
Commonwealth Scientific and Industrial Research Organisation, Plant Industry, G.P.O. Box 1600, Canberra ACT 2601, Australia.
Proc Natl Acad Sci U S A. 2008 Feb 12;105(6):2214-9. doi: 10.1073/pnas.0711453105. Epub 2008 Feb 4.
The epigenetic repression of FLOWERING LOCUS C (FLC) in winter-annual ecotypes of Arabidopsis by prolonged cold ensures that plants flower in spring and not during winter. Resetting of the FLC expression level in progeny is an important step in the life cycle of the plant. We show that both the paternally derived and the maternally derived FLC:GUS genes are reset to activity but that the timing of their first expression differs. The paternal FLC:GUS gene in vernalized plants is expressed in the male reproductive organs, the anthers, in both somatic tissue and in the sporogenous pollen mother cells, but there is no expression in mature pollen. In the progeny generation, the paternally derived FLC:GUS gene is expressed in the single-celled zygote (fertilized egg cell) and through embryo development, but not in the fertilized central cell, which generates the endosperm of the progeny seed. FLC:GUS is not expressed during female gametogenesis, with the maternally derived FLC:GUS being first expressed in the early multicellular embryo. We show that FLC activity during late embryo development is a prerequisite for the repressive action of FLC on flowering.
在拟南芥的冬性生态型中，长时间的低温对开花位点C（FLC）进行表观遗传抑制，确保植物在春季而非冬季开花。子代中FLC表达水平的重置是植物生命周期中的重要一步。我们发现，父本来源和母本来源的FLC:GUS基因均恢复活性，但其首次表达的时间不同。在经过春化处理的植物中，父本FLC:GUS基因在雄性生殖器官花药的体细胞组织和产孢花粉母细胞中均有表达，但在成熟花粉中无表达。在子代世代中，父本来源的FLC:GUS基因在单细胞合子（受精卵细胞）中表达，并贯穿胚胎发育过程，但不在产生子代种子胚乳的受精中央细胞中表达。FLC:GUS在雌配子发生过程中不表达，母本来源的FLC:GUS首先在早期多细胞胚胎中表达。我们表明，胚胎发育后期的FLC活性是FLC对开花起抑制作用的先决条件。
