Endosperm cellularization defines an important developmental transition for embryo development
Endosperm cellularization defines an important developmental transition for embryo development
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DOI：
10.1242/dev.077057
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发表时间：
2012-06-01
期刊：
影响因子：
4.6
通讯作者：
Kohler, Claudia
中科院分区：
文献类型：
--
作者：
Hehenberger, Elisabeth;Kradolfer, David;Kohler, Claudia
胚乳是种子的末端组织，注定要支持胚的发育。在大多数被子植物中，胚乳最初发育为合胞体，以促进种子的快速生长。从合胞体到细胞化状态的转变发生在种子发育期间的限定时间点。通过倍性间杂交操纵胚乳细胞化的时间对胚生长产生负面影响，表明胚乳细胞化是种子发育过程中的关键步骤。在这项研究中，我们表明，失败的胚乳细胞化受精独立的种子2（fis 2）和胚乳缺陷1（ede 1）拟南芥突变体与受损的胚胎发育。通过降低MADS盒基因AGAMOUS-LIKE 62（AGL 62）的表达恢复fis 2种子中的胚乳细胞化，促进胚胎发育，强烈支持胚乳细胞化对有活力种子形成的重要作用。fis 2种子中胚乳细胞化失败与己糖水平增加相关，表明胚胎发育停滞是营养物质转运到发育中的胚胎失败的结果。最后，我们证明了AGL 62是FIS Polycomb group repressive complex 2（PRC 2）的直接靶基因，为FIS PRC 2介导的胚乳细胞化奠定了分子基础。
The endosperm is a terminal seed tissue that is destined to support embryo development. In most angiosperms, the endosperm develops initially as a syncytium to facilitate rapid seed growth. The transition from the syncytial to the cellularized state occurs at a defined time point during seed development. Manipulating the timing of endosperm cellularization through interploidy crosses negatively impacts on embryo growth, suggesting that endosperm cellularization is a critical step during seed development. In this study, we show that failure of endosperm cellularization in fertilization independent seed 2 (fis2) and endosperm defective 1 (ede1) Arabidopsis mutants correlates with impaired embryo development. Restoration of endosperm cellularization in fis2 seeds by reducing expression of the MADS-box gene AGAMOUS-LIKE 62 (AGL62) promotes embryo development, strongly supporting an essential role of endosperm cellularization for viable seed formation. Endosperm cellularization failure in fis2 seeds correlates with increased hexose levels, suggesting that arrest of embryo development is a consequence of failed nutrient translocation to the developing embryo. Finally, we demonstrate that AGL62 is a direct target gene of FIS Polycomb group repressive complex 2 (PRC2), establishing the molecular basis for FIS PRC2-mediated endosperm cellularization.