TabHLH1, a bHLH-type transcription factor gene in wheat, improves plant tolerance to Pi and N deprivation via regulation of nutrient transporter gene transcription and ROS homeostasis
TabHLH1, a bHLH-type transcription factor gene in wheat, improves plant tolerance to Pi and N deprivation via regulation of nutrient transporter gene transcription and ROS homeostasis
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TabHLH1 是小麦中的 bHLH 型转录因子基因，通过调节养分转运蛋白基因转录和 ROS 稳态来提高植物对 Pi 和 N 缺乏的耐受性
DOI：
10.1016/j.plaphy.2016.03.023
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发表时间：
2016
影响因子：
6.5
通讯作者：
Xiao Kai
中科院分区：
文献类型：
--
作者：
Yang Tongren;Hao Lin;Yao Sufei;Zhao Yuanyuan;Lu Wenjing;Xiao Kai
碱性螺旋-环-螺旋（Basic helix-loop-helix，bHLH）转录因子是一类重要的转录因子家族，在植物的许多生理过程中起着重要的调节作用。在这里，我们报告的功能特性TabHLH 1，bHLH TF成员在小麦（Triticum aestivum）。TabHLH 1具有保守的bHLH结构域，靶向细胞核，具有反式激活活性。在缺磷和缺氮条件下，TabHLH 1在根和叶中的表达均呈上调趋势，且在23 h内呈逐渐增加的趋势。与野生型（WT）相比，过量表达TabHLH 1的植株表现出对缺磷和缺氮胁迫的耐受性显著提高，表现出更大的植株表型、更高的生物量、更高的磷和氮浓度以及更多的磷和氮积累。在TabHLH 1过表达的植物中表现出上调表达;敲除它们的表达会导致植物在缺磷和缺氮条件下生长特征恶化、生物量降低和营养积累减少。与野生型相比，过量表达TabHLH 1的植株体内活性氧（ROS）积累减少，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）等抗氧化酶（AE）活性提高，编码SOD、CAT和POD的NtSOD 1、NtCAT 1和NtPOD 1; 6表达上调。进一步敲低这些AE基因表达导致抗氧化酶活性降低，表明它们在Pi和N饥饿条件下介导细胞ROS稳态中的关键作用。总之，TabHLH 1通过转录调节一组编码PT、NRT和AE的基因在介导对Pi和N饥饿胁迫的适应中起重要作用，所述PT、NRT和AE介导由营养胁迫引发的Pi和N的摄取以及ROS的细胞内稳态。
Basic helix-loop-helix (bHLH) transcription factors (TFs) comprise a large TF family and act as crucial regulators in various biological processes in plants. Here, we report the functional characterization ofTabHLH1, a bHLH TF member in wheat (Triticum aestivum). TabHLH1 shares conserved bHLH domain and targets to nucleus with transactivation activity. Upon Pi and N deprivation, the expression ofTabHLH1was up-regulated in roots and leaves, showing a pattern to be gradually increased within 23-h treatment regimes. The lines with overexpression ofTabHLH1exhibited drastically improved tolerance to Pi and N deprivation, showing larger plant phenotype, more biomass, higher concentration and more accumulation of P and N than wild type (WT) upon the Pi- and N-starvation stresses.NtPT1andNtNRT2.2, the genes encoding phosphate transporter (PT) and nitrate transporter (NRT) in tobacco, respectively, showed up-regulated expression inTabHLH1-overexpressing plants; knockdown expression of them led to deteriorated growth feature, lowered biomass, and decreased nutrient accumulation of plants under Pi- and N-deficient conditions. Compared with WT, theTabHLH1-overexpressing plants also showed lowered reactive oxygen species (ROS) accumulation and improved antioxidant enzyme (AE) activities, such as those of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD).NtSOD1,NtCAT1, andNtPOD1;6that encode SOD, CAT, and POD, respectively, were up-regulated inTabHLH1-overexpressing plants. Further knockdown of these AE gene expression caused reduced antioxidant enzymatic activities, indicative of their crucial roles in mediating cellular ROS homeostasis in Pi- and N-starvation conditions. Together,TabHLH1plays an important role in mediating adaptation to the Pi- and N-starvation stresses through transcriptional regulation of a set of genes encoding PT, NRT and AEs that mediate the taken up of Pi and N and the cellular homeostasis of ROS initiated by the nutrient stresses.