Wheat ZFP gene TaZFP593;l mediates the N-starvation adaptation of plants through regulating N acquisition and the ROS metabolism

Abstract

The responsiveness of plants to abiotic stresses is closely associated with the transcription factors (TFs) through their transcriptional regulation of the downstream defensive genes. In this study, we characterized the role of TaZFP593;l, a C2H2 type gene encoding the zinc finger protein (ZFP) in wheat (T. aestivum), in mediating plants to acclimate to the N-starvation stress. TaZFP593;l bears a conserved C2H2 motif and targets to nucleus after sorted from endoplasmic reticulum. Upon N deprivation, TaZFP593;l showed induced transcripts in the roots and leaves, suggesting that its expression is transcriptionally regulated by the N-starvation stress. Analysis on the transgenic tobacco lines with overexpression of TaZFP593;l revealed that this wheat gene conferred plants improved adaptation to N deprivation; the lines displayed enlarged phenotype and root system architecture (RSA), increased biomass and N amount, and improved cellular reactive oxygen species (ROS) homeostasis relative to the wild type. Expression analysis indicated that the PIN-FORMED (PIN) gene NtPIN3, nitrate transporter (NRT) genes NtNRT1.2-t and NtNRT2.2, catalase genes NtCAT1 and NtCAT3, and the peroxidase genes NtPOD1;1, NtPOD1;7, NtPOD2;1 and NtPOD9 showed differentially upregulated expression in the N-deprived TaZFP593;l overexpression lines, suggesting that these differential genes are involved in the improvement of root system formation, nitrogen taken up, CAT activity, and POD activity, respectively, in the TaZFP593;l overexpression plants challenged by the N-starvation stress. The nitrogen assimilation-associated parameters, such as the activities of nitrate reductase (NR), nitrite reductase (NIR), and the glutamine synthetase (GS) and the expression levels of genes coding for NR, NIR, and GS were all comparable between the TaZFP593;l overexpression lines and the wild type, suggesting that the TaZFP593;l can not affect the nitrogen assimilation processes of plants once treated by low-N stress. Our investigation indicates that the wheat ZFP encoding gene TaZFP593;l play an essential role in mediating plant N-starvation adaptation through improving RSA establishment, nitrogen acquisition, and cellular ROS homeostasis via its role in transcriptionally regulating the genes associating with above physiological processes.