Vernalization-induced flowering in cereals is associated with changes in histone methylation at the VERNALIZATION1 gene
Vernalization-induced flowering in cereals is associated with changes in histone methylation at the VERNALIZATION1 gene
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DOI：
10.1073/pnas.0903566106
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发表时间：
2009-05-19
影响因子：
11.1
通讯作者：
Trevaskis, Ben
中科院分区：
文献类型：
--
作者：
Oliver, Sandra N.;Finnegan, E. Jean;Trevaskis, Ben
长时间暴露于低温（春化作用）加速了许多植物物种向生殖生长的过渡，包括模式植物拟南芥和经济上重要的谷类作物、小麦和大麦。春化诱导开花是一种表观遗传现象。在拟南芥中，通过春化作用稳定下调FLC基因座C（FLC）与FLC染色质组蛋白修饰的变化有关。在谷类植物中，春化反应是由成花启动子VERNALIZATION 1（VRN 1）的稳定诱导介导的，该启动子在茎尖启动生殖发育。我们发现，在大麦（大麦），春化前HvVRN 1的镇压与高水平的组蛋白3赖氨酸27三甲基化（H3 K27 me 3）在HvVRN 1染色质。春化引起组蛋白3赖氨酸4三甲基化（H3 K4 me 3）的水平增加和H3 K27 me 3在HvVRN 1的损失，表明春化促进VRN 1的活性染色质状态。这些组蛋白修饰的水平在其他2个开花时间基因，VERNALIZATION 2和FLOWALIZLOCUS T，没有改变春化。我们的研究表明，维持一个活跃的染色质状态VRN 1可能是表观遗传记忆的基础上，在谷物春化。因此，染色质状态的调节是拟南芥和谷类植物中春化作用的表观遗传记忆的一个特征;然而，拟南芥中春化作用诱导的开花是由花阻遏物FLC的表观遗传调节介导的，而谷类植物中的这种现象是由花激活物VRN 1的表观遗传调节介导的。
Prolonged exposure to low temperatures (vernalization) accelerates the transition to reproductive growth in many plant species, including the model plant Arabidopsis thaliana and the economically important cereal crops, wheat and barley. Vernalization-induced flowering is an epigenetic phenomenon. In Arabidopsis, stable down-regulation of FLOWERING LOCUS C (FLC) by vernalization is associated with changes in histone modifications at FLC chromatin. In cereals, the vernalization response is mediated by stable induction of the floral promoter VERNALIZATION1 (VRN1), which initiates reproductive development at the shoot apex. We show that in barley (Hordeum vulgare), repression of HvVRN1 before vernalization is associated with high levels of histone 3 lysine 27 trimethylation (H3K27me3) at HvVRN1 chromatin. Vernalization caused increased levels of histone 3 lysine 4 trimethylation (H3K4me3) and a loss of H3K27me3 at HvVRN1, suggesting that vernalization promotes an active chromatin state at VRN1. Levels of these histone modifications at 2 other flowering-time genes, VERNALIZATION2 and FLOWERING LOCUS T, were not altered by vernalization. Our study suggests that maintenance of an active chromatin state at VRN1 is likely to be the basis for epigenetic memory of vernalization in cereals. Thus, regulation of chromatin state is a feature of epigenetic memory of vernalization in Arabidopsis and the cereals; however, whereas vernalization-induced flowering in Arabidopsis is mediated by epigenetic regulation of the floral repressor FLC, this phenomenon in cereals is mediated by epigenetic regulation of the floral activator, VRN1.