AUTHOR=Liu Jinyuan , Yang Ruirui , Liang Yuqing , Wang Yan , Li Xiaoshuang 

TITLE=The DREB A-5 Transcription Factor ScDREB5 From Syntrichia caninervis Enhanced Salt Tolerance by Regulating Jasmonic Acid Biosynthesis in Transgenic Arabidopsis

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.857396

DOI=10.3389/fpls.2022.857396

ISSN=1664-462X

ABSTRACT=<p>Salinity is a major limiting factor in crop productivity. Dehydration-responsive element-binding protein (DREB) transcription factors have been widely identified in a variety of plants and play important roles in plant stress responses. Studies on DREBs have primarily focused on the A-1 and A-2 DREB groups, while few have focused on the A-5 group. In this study, we concentrated on <italic>ScDREB5</italic>, an A-5b type <italic>DREB</italic> gene from the desiccation-tolerant moss <italic>Syntrichia caninervis</italic>. <italic>ScDREB5</italic> is a transcription factor localized to the nucleus that exhibits transactivation activity in yeast. Ectopic <italic>ScDREB5</italic> expression in <italic>Arabidopsis thaliana</italic> increased seed germination and improved seedling tolerance under salt stress. <italic>ScDREB5</italic>-overexpression transgenic Arabidopsis lines showed lower methane dicarboxylic aldehyde (MDA) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) contents, but higher peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities compared to wild plants. Moreover, the transcriptional levels of stress marker genes, including <italic>RD29B</italic>, <italic>COR47</italic>, <italic>LEA6</italic>, <italic>LEA7</italic>, <italic>ERD1</italic>, <italic>P5CS1</italic>, and salt overly sensitive (SOS) genes (<italic>SOS1</italic>, <italic>SOS2</italic>, and <italic>SOS3</italic>), were upregulated in the transgenic lines when subjected to salt treatment. Transcriptome and real-time quantitative PCR (RT-qPCR) analyses indicated that transgenic lines were accompanied by an increased expression of jasmonic acid (JA) biosynthesis genes, as well as a higher JA content under salt stress. Our results suggest that <italic>ScDREB5</italic> could improve salt tolerance by enhancing the scavenging abilities of reactive oxygen species (ROS), increasing JA content by upregulating JA synthesis gene expression, regulating ion homeostasis by up-regulating stress-related genes, osmotic adjustment, and protein protection, making <italic>ScDREB5</italic> a promising candidate gene for crop salt stress breeding.</p>