Fertilization Independent Endosperm genes repress NbGH3.6 and regulate the auxin level during shoot development in Nicotiana benthamiana.
Fertilization Independent Endosperm genes repress NbGH3.6 and regulate the auxin level during shoot development in Nicotiana benthamiana.
复制标题
本塞姆氏烟草芽发育过程中受精独立胚乳基因抑制 NbGH3.6 并调节生长素水平
DOI：
10.1093/jxb/erw024
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发表时间：
2016-04
影响因子：
6.9
通讯作者：
He XQ
中科院分区：
文献类型：
--
作者：
Zeng J;Ding Q;Fukuda H;He XQ
不依赖于受精的胚乳基因通过调节生长素的体内平衡来控制烟草的枝分枝和次生木质部分化，可能是通过组蛋白甲基化标记H3 K27 me 3来抑制NbGH3.6基因。不依赖受精的胚乳（FIE）基因是限制不受精的胚乳发育所必需的，并且它抑制拟南芥胚胎和幼苗发育过程中的开花。然而，FIE基因在胚后芽发育中的调控机制尚不清楚。沉默本氏烟草的FIE基因，NbFIE 1和NbFIE 2的同源物，导致腋芽的生长增强和次生木质部分化的损害。RNA测序分析发现，生长素响应的GRETCHEN哈根3（GH 3）家族基因之一NbGH3.6在沉默NbFIE基因的时间过程中被上调并保持高表达。染色质免疫印迹（ChIP）-PCR结果显示，与阴性对照相比，NbFIE沉默植株的NbGH3.6染色质上缺少H3 K27 me 3标记，表明NbGH3.6是NbFIE基因在胚后芽发育过程中的直接靶基因。此外，NbFIE沉默植株中游离IAA含量显著降低，这可能导致腋芽生长增强以及次生木质部分化受损。这些结果清楚地表明，NbGH3.6是NbFIE基因在胚后芽发育过程中的主要靶标，NbFIE基因通过调节内源生长素的稳态来调节腋芽的生长和次生木质部的形成，可能是通过调节NbGH3.6基因的表达。
Fertilization Independent Endosperm genes control shoot branching and secondary xylem differentiation in Nicotiana benthamiana by tuning auxin homeostasis, possibly by repressing the NbGH3.6 gene through the histone methylation mark H3K27me3. The Fertilization Independent Endosperm (FIE) gene is required to restrict endosperm development without fertilization, and it represses flowering during embryo and seedling development in Arabidopsis thaliana. However, the regulatory mechanism of the FIE gene in postembryonic shoot development is not well understood. Silencing of Nicotiana benthamiana homologues of the FIE gene, NbFIE1 and NbFIE2, resulted in the enhanced outgrowth of axillary buds and the impairment of secondary xylem differentiation. RNA sequencing analysis found that one of the auxin-responsive GRETCHEN HAGEN 3 (GH3) family genes, NbGH3.6, was upregulated and maintained a high expression during the time course of silencing NbFIE genes. Chromatin immunoprecipiation (ChIP)-PCR results showed a lack of H3K27me3 marks on NbGH3.6 chromatin in NbFIE-silenced plants compared with negative control plants, indicating that NbGH3.6 was a direct target of NbFIE genes during postembryonic shoot development. Moreover, the free IAA content was reduced significantly in NbFIE-silenced plants, which might cause the enhanced outgrowth of axillary buds as well as impaired secondary xylem differentiation. These results clearly indicated that NbGH3.6 was a primary target of NbFIE genes during postembryonic shoot development, and NbFIE genes regulated axillary bud growth and secondary xylem formation through tuning endogenous auxin homeostasis, possibly by regulating the expression of the NbGH3.6 gene.