The Maize Transcription Factor Myb-Related Protein-1 Is a Key Regulator of the Differentiation of Transfer Cells
The Maize Transcription Factor Myb-Related Protein-1 Is a Key Regulator of the Differentiation of Transfer Cells
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DOI：
10.1105/tpc.108.065409
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发表时间：
2009-07-01
期刊：
影响因子：
11.6
通讯作者：
Hueros, Gregorio
中科院分区：
文献类型：
--
作者：
Gomez, Elisa;Royo, Joaquin;Hueros, Gregorio
转移细胞是高度修饰的植物细胞，专门用于溶质的运输。它们在许多植物交换表面上分化，包括韧皮部装载和卸载区，例如存在于库器官和种子中的那些。在玉米种子中，传递细胞位于胚乳的基部。目前尚不清楚顶基极性是如何建立的，也不知道胚乳基部的外周细胞为什么分化成转移细胞而不是糊粉细胞。在这里，我们表明，在表皮细胞致力于发展成糊粉细胞，异位表达的转移细胞特异性转录激活Myb相关蛋白-1（MRP-1）是足以暂时将它们转化为转移细胞。这些转化细胞获得不同的转移细胞特征，如细胞壁向内生长和细长形状。此外，它们还表达许多可能参与防御的MRP-1靶基因。我们还表明MRP-1的表达是维持转移细胞表型所必需的。在发育后期，观察到MRP-1的异位表达减少，随后是转化细胞的逆转，然后获得糊粉细胞特征。
Transfer cells are highly modified plant cells specialized in the transport of solutes. They differentiate at many plant exchange surfaces, including phloem loading and unloading zones such as those present in the sink organs and seeds. In maize (Zea mays) seeds, transfer cells are located at the base of the endosperm. It is currently unknown how apical-basal polarity is established or why the peripheral cells at the base of the endosperm differentiate into transfer instead of aleurone cells. Here, we show that in epidermal cells committed to develop into aleurone cells, the ectopic expression of the transfer cell-specific transcriptional activator Myb-Related Protein-1 (MRP-1) is sufficient to temporarily transform them into transfer cells. These transformed cells acquire distinct transfer cell features, such as cell wall ingrowths and an elongated shape. In addition, they express a number of MRP-1 target genes presumably involved in defense. We also show that the expression of MRP-1 is needed to maintain the transfer cell phenotype. Later in development, an observed reduction in the ectopic expression of MRP-1 was followed by the reversion of the transformed cells, which then acquire aleurone cell features.