Bouveret Romaric, Schönrock Nicole, Gruissem Wilhelm, Hennig Lars
Institute of Plant Sciences and Zurich-Basel Plant Science Center, ETH Zurich, LFW E17, CH-8092 Zurich, Switzerland.
Development. 2006 May;133(9):1693-702. doi: 10.1242/dev.02340. Epub 2006 Mar 22.
The transition to flowering is tightly controlled by endogenous programs and environmental signals. We found that MSI1 is a novel flowering-time gene in Arabidopsis. Both partially complemented msi1 mutants and MSI1 antisense plants were late flowering, whereas ectopic expression of MSI1 accelerated flowering. Physiological experiments revealed that MSI1 is similar to genes from the autonomous promotion of flowering pathway. Expression of most known flowering-time genes did not depend on MSI1, but the induction of SOC1 was delayed in partially complemented msi1 mutants. Delayed activation of SOC1 is often caused by increased expression of the floral repressor FLC. However, MSI1 function is independent of FLC. MSI1 is needed to establish epigenetic H3K4 di-methylation and H3K9 acetylation marks in SOC1 chromatin. The presence of these modifications correlates with the high levels of SOC1 expression that induce flowering in Arabidopsis. Together, the control of flowering time depends on epigenetic mechanisms for the correct expression of not only the floral repressor FLC, but also the floral activator SOC1.
向开花的转变受到内源程序和环境信号的严格控制。我们发现MSI1是拟南芥中一个新的开花时间基因。部分互补的msi1突变体和MSI1反义植株均开花延迟，而MSI1的异位表达则加速了开花。生理实验表明，MSI1与自主促进开花途径中的基因相似。大多数已知开花时间基因的表达不依赖于MSI1，但在部分互补的msi1突变体中，SOC1的诱导延迟。SOC1的延迟激活通常是由花抑制因子FLC表达增加引起的。然而，MSI1的功能独立于FLC。在SOC1染色质中建立表观遗传的H3K4二甲基化和H3K9乙酰化标记需要MSI1。这些修饰的存在与诱导拟南芥开花的高水平SOC1表达相关。总之，开花时间的控制不仅取决于表观遗传机制对花抑制因子FLC的正确表达，还取决于对花激活因子SOC1的正确表达。
