The Progression of Xylem Vessel Cell Differentiation is Dependent on the Activity Level of VND7 in Arabidopsis thaliana
The Progression of Xylem Vessel Cell Differentiation is Dependent on the Activity Level of VND7 in Arabidopsis thaliana
复制标题
拟南芥木质部导管细胞分化的进程依赖于VND7的活性水平
DOI：
10.3390/plants9010039
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发表时间：
2020-01-01
期刊：
影响因子：
4.5
通讯作者：
Ohtani, Misato
中科院分区：
文献类型：
--
作者：
Hirai, Risaku;Higaki, Takumi;Ohtani, Misato
木质部导管在维管植物中起着重要的水传导作用。维管相关NAC-DOMAIN （VND）家族蛋白是拟南芥木质部导管细胞分化的主要调控因子，可上调木质部导管细胞分化所需的一系列基因，包括与次生细胞壁（SCW）形成和程序性细胞死亡（PCD）相关的基因；然而，目前还不完全清楚VND活动水平如何影响这些过程。在这里，我们研究了拟南芥VND7- vp16 - gr系，其中VND7活性在不同浓度的合成糖皮质激素地塞米松（DEX）处理下被翻译后激活。结果表明，1 nM DEX诱导弱SCW沉积，但不诱导PCD，而10或100 nM DEX同时诱导SCW沉积和PCD。在100 nM DEX处理24 h后，叶绿素含量和SCW沉积明显下降，但在10 nM DEX处理48 h后才出现明显下降。此外，较低的DEX浓度延迟了VND7下游基因的上调，降低了其诱导水平。他们共同表明，VND活性的调节不仅对启动木质部导管细胞分化很重要，而且还通过VND活性依赖的PCD和scw相关基因的上调来调节木质部导管的质量。
Xylem vessels are important for water conduction in vascular plants. The VASCULAR-RELATED NAC-DOMAIN (VND) family proteins, master regulators of xylem vessel cell differentiation in Arabidopsis thaliana, can upregulate a set of genes required for xylem vessel cell differentiation, including those involved in secondary cell wall (SCW) formation and programmed cell death (PCD); however, it is not fully understood how VND activity levels influence these processes. Here, we examined the Arabidopsis VND7-VP16-GR line, in which VND7 activity is post-translationally activated by treatments with different concentrations of dexamethasone (DEX), a synthetic glucocorticoid. Our observations showed that 1 nM DEX induced weak SCW deposition, but not PCD, whereas 10 or 100 nM DEX induced both SCW deposition and PCD. The decreased chlorophyll contents and SCW deposition were apparent after 24 h of 100 nM DEX treatment, but became evident only after 48 h of 10 nM DEX treatment. Moreover, the lower DEX concentrations delayed the upregulation of VND7 downstream genes, and decreased their induction levels. They collectively suggest that the regulation of VND activity is important not only to initiate xylem vessel cell differentiation, but also regulate the quality of the xylem vessels through VND-activity-dependent upregulation of the PCD- and SCW-related genes.