AUTHOR=Chen YiQing , Zhou Yan , Cai Yuyi , Feng Yongpei , Zhong Cairong , Fang ZanShan , Zhang Ying 

TITLE=De novo transcriptome analysis of high-salinity stress-induced antioxidant activity and plant phytohormone alterations in Sesuvium portulacastrum

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.995855

DOI=10.3389/fpls.2022.995855

ISSN=1664-462X

ABSTRACT=<p><italic>Sesuvium portulacastrum</italic> has a strong salt tolerance and can grow in saline and alkaline coastal and inland habitats. This study investigated the physiological and molecular responses of <italic>S. portulacastrum</italic> to high salinity by analyzing the changes in plant phytohormones and antioxidant activity, including their differentially expressed genes (DEGs) under similar high-salinity conditions. High salinity significantly affected proline (Pro) and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) in <italic>S. portulacastrum</italic> seedlings, increasing Pro and H<sub>2</sub>O<sub>2</sub> contents by 290.56 and 83.36%, respectively, compared to the control. Antioxidant activities, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), significantly increased by 83.05, 205.14, and 751.87%, respectively, under high salinity. Meanwhile, abscisic acid (ABA) and gibberellic acid (GA<sub>3</sub>) contents showed the reverse trend of high salt treatment. <italic>De novo</italic> transcriptome analysis showed that 36,676 unigenes were matched, and 3,622 salt stress-induced DEGs were identified as being associated with the metabolic and biological regulation processes of antioxidant activity and plant phytohormones. POD and SOD were upregulated under high-salinity conditions. In addition, the transcription levels of genes involved in auxin (<italic>SAURs</italic> and <italic>GH3</italic>), ethylene (<italic>ERF1</italic>, <italic>ERF3</italic>, <italic>ERF114</italic>, and <italic>ABR1</italic>), ABA (<italic>PP2C</italic>), and GA<sub>3</sub> (<italic>PIF3</italic>) transport or signaling were altered. This study identified key metabolic and biological processes and putative genes involved in the high salt tolerance of <italic>S. portulacastrum</italic> and it is of great significance for identifying new salt-tolerant genes to promote ecological restoration of the coastal strand.</p>