ZmDof3, a maize endosperm-specific Dof protein gene, regulates starch accumulation and aleurone development in maize endosperm
ZmDof3, a maize endosperm-specific Dof protein gene, regulates starch accumulation and aleurone development in maize endosperm
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ZmDof3是玉米胚乳特异性Dof蛋白基因，调节玉米胚乳中淀粉积累和糊粉发育
DOI：
10.1007/s11103-016-0543-y
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发表时间：
2017-01-01
影响因子：
5.1
通讯作者：
Yu, Jingjuan
中科院分区：
文献类型：
--
作者：
Qi, Xin;Li, Shixue;Yu, Jingjuan
为了探索Dof转录因子在玉米籽粒发育中的功能，我们首先鉴定了玉米基因组中的Dof基因。我们发现ZmDof3只在玉米籽粒胚乳中表达，具有Dof转录因子的特征。ZmDof3的抑制导致淀粉含量降低和部分斑片状糊粉层的有缺陷的籽粒表型。ZmDof3基因敲除后玉米籽粒中淀粉合成相关基因和糊粉层分化相关基因的表达水平均下调，表明ZmDof3基因在玉米胚乳发育中起着重要作用。目前关于胚乳发育调控的知识是有限的。Dof蛋白是一类植物特异性转录因子，在多种生物学过程中发挥着重要作用。本研究通过全基因组筛选，在玉米中鉴定出胚乳特异性Dof蛋白基因ZmDof3。ZmDof3的抑制导致有缺陷的籽粒表型。电镜下观察到ZmDof3基因敲除的籽粒胚乳疏松，淀粉颗粒排列不规则。通过全基因组表达谱分析，我们发现下调的基因在与碳水化合物代谢相关的GO术语中富集。ZmDof3在体内外均能与淀粉合成基因Du1和Su2启动子中的Dof核心元件结合。此外，成熟ZmDof3基因敲除籽粒中局部位置的糊粉层由一至三层不等，由较小且不规则的细胞组成。进一步的分析表明，ZmDof3的敲低降低了参与糊粉细胞分化的Nkd1的表达，并且ZmDof3可以结合Nkd1启动子中的Dof核心元件。我们的研究表明，ZmDof3功能在玉米胚乳发育作为一个积极的调节器在信号系统控制淀粉积累和糊粉层的发展。
To explore the function of Dof transcription factors during kernel development in maize, we first identified Dof genes in the maize genome. We found that ZmDof3 was exclusively expressed in the endosperm of maize kernel and had the features of a Dof transcription factor. Suppression of ZmDof3 resulted in a defective kernel phenotype with reduced starch content and a partially patchy aleurone layer. The expression levels of starch synthesis-related genes and aleurone differentiation-associated genes were down-regulated in ZmDof3 knockdown kernels, indicating that ZmDof3 plays an important role in maize endosperm development.The maize endosperm, occupying a large proportion of the kernel, plays an important role in seed development and germination. Current knowledge regarding the regulation of endosperm development is limited. Dof proteins, a family of plant-specific transcription factors, play critical roles in diverse biological processes. In this study, an endosperm-specific Dof protein gene, ZmDof3, was identified in maize through genome-wide screening. Suppression of ZmDof3 resulted in a defective kernel phenotype. The endosperm of ZmDof3 knockdown kernels was loosely packed with irregular starch granules observed by electronic microscope. Through genome-wide expression profiling, we found that down-regulated genes were enriched in GO terms related to carbohydrate metabolism. Moreover, ZmDof3 could bind to the Dof core element in the promoter of starch biosynthesis genes Du1 and Su2 in vitro and in vivo. In addition, the aleurone at local position in mature ZmDof3 knockdown kernels varied from one to three layers, which consisted of smaller and irregular cells. Further analyses showed that knockdown of ZmDof3 reduced the expression of Nkd1, which is involved in aleurone cell differentiation, and that ZmDof3 could bind to the Dof core element in the Nkd1 promoter. Our study reveals that ZmDof3 functions in maize endosperm development as a positive regulator in the signaling system controlling starch accumulation and aleurone development.