Opaque-2 Regulates a Complex Gene Network Associated with Cell Differentiation and Storage Functions of Maize Endosperm
Opaque-2 Regulates a Complex Gene Network Associated with Cell Differentiation and Storage Functions of Maize Endosperm
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DOI：
10.1105/tpc.18.00392
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发表时间：
2018-10-01
期刊：
影响因子：
11.6
通讯作者：
Yadegari, Ramin
中科院分区：
文献类型：
--
作者：
Zhan, Junpeng;Li, Guosheng;Yadegari, Ramin
谷物胚乳的发育涉及细胞分化过程，该过程使得能够从母本植物吸收养分、储存产物的积累以及它们在发芽期间的利用。然而，人们对将细胞分化过程与控制储存产物合成和沉积联系起来的调节机制知之甚少，包括玉米（Zea mays）bZIP转录因子Opaque-2 (O2)激活玉米醇溶蛋白基因。在这里，我们绘制了 B73 胚乳中 O2 的体内结合位点，并将结果与 B73 和 B73o2 中差异表达的基因进行了比较。我们确定了 186 个假定的直接 O2 目标和 1677 个间接目标，编码了广泛的基因功能。对 O2 靶标的时间表达模式的检查揭示了至少两种不同的 O2 介导的基因激活模式。两个 O2 激活基因 bZIP17 和 NAKED ENDOSPERM2 (NKD2) 编码转录因子，这反过来又可以与 O2 共同激活其他 O2 网络基因。 NKD2（及其旁系同源物 NKD1）先前已被证明参与糊粉发育的调节。总的来说，我们的结果提供了对 O2 调节网络的复杂性及其在胚乳细胞分化和功能调节中的作用的见解。
Development of the cereal endosperm involves cell differentiation processes that enable nutrient uptake from the maternal plant, accumulation of storage products, and their utilization during germination. However, little is known about the regulatory mechanisms that link cell differentiation processes with those controlling storage product synthesis and deposition, including the activation of zein genes by the maize (Zea mays) bZIP transcription factor Opaque-2 (O2). Here, we mapped in vivo binding sites of O2 in B73 endosperm and compared the results with genes differentially expressed in B73 and B73o2. We identified 186 putative direct O2 targets and 1677 indirect targets, encoding a broad set of gene functionalities. Examination of the temporal expression patterns of O2 targets revealed at least two distinct modes of O2-mediated gene activation. Two O2-activated genes, bZIP17 and NAKED ENDOSPERM2 (NKD2), encode transcription factors, which can in turn coactivate other O2 network genes with O2. NKD2 (with its paralog NKD1) was previously shown to be involved in regulation of aleurone development. Collectively, our results provide insights into the complexity of the O2-regulated network and its role in regulation of endosperm cell differentiation and function.