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.
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 of TabHLH1, 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 of TabHLH1 was up-regulated in roots and leaves, showing a pattern to be gradually increased within 23-h treatment regimes. The lines with overexpression of TabHLH1 exhibited 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. NtPT1 and NtNRT2.2, the genes encoding phosphate transporter (PT) and nitrate transporter (NRT) in tobacco, respectively, showed up-regulated expression in TabHLH1-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, the TabHLH1-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, and NtPOD1;6 that encode SOD, CAT, and POD, respectively, were up-regulated in TabHLH1-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, TabHLH1 plays 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.
College of Life Sciences, Agricultural University of Hebei, Baoding, 071001, China.
Tongren
T
Yang
College of Agronomy, Agricultural University of Hebei, Baoding, 071001, China; College of Life Sciences, Agricultural University of Hebei, Baoding, 071001, China.
Lin
L
Hao
College of Agronomy, Agricultural University of Hebei, Baoding, 071001, China; College of Life Sciences, Agricultural University of Hebei, Baoding, 071001, China.
Sufei
S
Yao
College of Agronomy, Agricultural University of Hebei, Baoding, 071001, China.
Yuanyuan
Y
Zhao
College of Life Sciences, Agricultural University of Hebei, Baoding, 071001, China. Electronic address: luwenjing@sohu.com.
Wenjing
W
Lu
College of Agronomy, Agricultural University of Hebei, Baoding, 071001, China. Electronic address: xiaokai@hebau.edu.cn.
Kai
K
Xiao
D000222:Adaptation, Physiological / Q000187:drug effects*; D000595:Amino Acid Sequence; D000975:Antioxidants / Q000378:metabolism; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000737:chemistry / Q000378:metabolism; D018533:Biomass; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D006706:Homeostasis / Q000187:drug effects / Q000235:genetics; D009584:Nitrogen / Q000494:pharmacology*; D010758:Phosphorus / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D000072417:Protein Domains; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic / Q000187:drug effects*; D015533:Transcriptional Activation / Q000187:drug effects; D014908:Triticum / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects
D000975:Antioxidants; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D010940:Plant Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D010758:Phosphorus; D009584:Nitrogen
Expression pattern; Phosphate and nitrate transporter; Pi and N deprivation; Reactive oxygen species (ROS); Transgene analysis; Wheat (Triticum aestivum L.); bHLH transcription factor