關(guān)于植物開花時間調(diào)控的大多數(shù)研究都是對一年生植物進行的,，如經(jīng)典的“實驗室植物”擬南芥就是這樣,，它們一生只開一次花。多年生植物可以生長很多年,，開花與營養(yǎng)生長周期反復(fù)出現(xiàn),。關(guān)于它們的開花時間是如何調(diào)控的是一個可能更為復(fù)雜的問題，而人們對此所做的研究卻要少得多,。
現(xiàn)在,，對“高山南芥”（一種與擬南芥相關(guān)的多年生植物）的開花所做的一項研究識別出一個基因，即PEP1 (“永久開花”-1),，它調(diào)控多年生植物的三個關(guān)鍵特征,。該基因參與限制開花持續(xù)時間、徹底阻止某些枝條開花以及將開花限制在春天等,。PEP1是擬南芥中FLC開花抑制基因的直系同源基因,，后者通過染色質(zhì)修飾抑制開花,，直到植物暴露于低氣溫,。PEP1在多年生植物中所具有的功能在一年生植物中不存在，這些功能似乎是通過在FLC 和PEP1位點的組蛋白修飾的變化形成的,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 459, 423-427 (21 May 2009) | doi:10.1038/nature07988
PEP1 regulates perennial flowering in Arabis alpina
Renhou Wang1, Sara Farrona1, Coral Vincent1, Anika Joecker1, Heiko Schoof1, Franziska Turck1, Carlos Alonso-Blanco2, George Coupland1 & Maria C. Albani1
1 Max Planck Institute for Plant Breeding Research, Carl von Linne Weg 10, D-50829 Cologne, Germany
2 Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Científicas), Cantoblanco, 28049 Madrid, Spain
Annual plants complete their life cycle in one year and initiate flowering only once, whereas perennials live for many years and flower repeatedly. How perennials undergo repeated cycles of vegetative growth and flowering that are synchronized to the changing seasons has not been extensively studied1. Flowering is best understood in annual Arabidopsis thaliana 2, 3, but many closely related species, such as Arabis alpina 4, 5, are perennials. We identified the A. alpina mutant perpetual flowering 1 (pep1), and showed that PEP1 contributes to three perennial traits. It limits the duration of flowering, facilitating a return to vegetative development, prevents some branches from undergoing the floral transition allowing polycarpic growth habit, and confers a flowering response to winter temperatures that restricts flowering to spring. Here we show that PEP1 is the orthologue of the A. thaliana gene FLOWERING LOCUS C (FLC). The FLC transcription factor inhibits flowering until A. thaliana is exposed to winter temperatures6, 7, which trigger chromatin modifications that stably repress FLC transcription8, 9, 10, 11. In contrast, PEP1 is only transiently repressed by low temperatures, causing repeated seasonal cycles of repression and activation of PEP1 transcription that allow it to carry out functions characteristic of the cyclical life history of perennials. The patterns of chromatin modifications at FLC and PEP1 differ correlating with their distinct expression patterns. Thus we describe a critical mechanism by which flowering regulation differs between related perennial and annual species, and propose that differences in chromatin regulation contribute to this variation.
