<i>Tamarix hispida</i> NAC Transcription Factor <i>ThNAC4</i> Confers Salt and Drought Stress Tolerance to Transgenic <i>Tamarix</i> and <i>Arabidopsis</i>

Salt and drought are considered two major abiotic stresses that have a significant impact on plants. Plant NAC (NAM, ATAF1/2, and CUC2) transcription factors (TFs) have been shown to play vital roles in plant development and responses to various abiotic stresses. ThNAC4, a NAC gene from Tamarix hispida involved in salt and osmotic stress tolerance, was identified and characterized in this study. According to a phylogenetic study, ThNAC4 is a member of NAC subfamily II. Subcellular localization analysis showed that ThNAC4 is located in the nucleus, and transcriptional activation experiments demonstrated that ThNAC4 is a transcriptional activator. Transgenic Arabidopsis plants overexpressing ThNAC4 exhibited improved salt and osmotic tolerance, as demonstrated by improved physiological traits. ThNAC4-overexpressing and ThNAC4-silenced T. hispida plants were generated using the transient transformation method and selected for gain- and loss-of-function analysis. The results showed that overexpression of ThNAC4 in transgenic Tamarix and Arabidopsis plants increased the activities of antioxidant enzymes (SOD, POD, and GST) and osmoprotectant (proline and trehalose) contents under stress conditions. These findings suggest that ThNAC4 plays an important physiological role in plant abiotic stress tolerance by increasing ROS scavenging ability and improving osmotic potential

<i>ScDREB10</i>, an A-5c type of <i>DREB</i> Gene of the Desert Moss <i>Syntrichia caninervis</i>, Confers Osmotic and Salt Tolerances to <i>Arabidopsis</i>

Drought and salinity are major factors limiting crop productivity worldwide. DREB (dehydration-responsive element-binding) transcription factors play important roles in plant stress response and have been identified in a wide variety of plants. Studies on DREB are focused on the A-1 (DREB1) and A-2 (DREB2) groups. Studies on A-5 group DREBs, which represent a large proportion of the DREB subfamily, is limited. In this study, we characterized and analyzed the stress tolerance function of ScDREB10, an A-5c type DREB gene from the desert moss Syntrichia caninervis. Transactivation assay in yeast showed that ScDREB10 had transactivation activity. Transient expression assay revealed that ScDREB10 was distributed both in the nucleus and cytosol of tobacco leaf epidermal cells. Overexpression of ScDREB10 significantly increased the germination percentage of Arabidopsis seeds under osmotic and salt stresses, and improved the osmotic and salt stress tolerances of Arabidopsis at the seedling stage and is associated with the expression of downstream stress-related genes and improved reactive oxygen species (ROS) scavenging ability. Our study provides insight into the molecular mechanism of stress tolerance of A-5 type DREB proteins, as well as providing a promising candidate gene for crop salt and drought stress breeding