Transcriptome analysis revealed MAPK and hormone pathway involving in exogenous melatonin-regulated salt tolerance in sour jujube

Abstract

Melatonin (MT) plays an important role in plant growth and development, and response to biotic and abiotic stresses. Salt stress is one of the major abiotic stresses affecting plant growth and distribution. Sour jujube mainly grows in mountainous sandy land and faces the threat of salt stress. Thus, to explore whether exogenous MT application could improve the salt stress tolerance of sour jujube and reveal the molecular mechanism behind it, the phenotypic and transcriptomic analyses of different concentrations of MT treatments prior to sodium chloride (NaCl) treatment to sour jujube was investigated. Firstly, exogenous MT treatment has a certain alleviating effect on salt stress induced damage of sour jujube. Transcriptome analysis showed that 6,292, 2,795, and 4,198 differentially expressed genes (DEGs) were identified in water treatment (W) vs 400 mmol/L NaCl treatment (Na), W vs 10 µmol/L MT plus 400 mmol/L NaCl treatment (MNa), and Na vs MNa comparative groups, respectively. KEGG enrichment analysis of DEGs showed that multiple metabolic pathways were involved in MT regulated effect on salt stress, including mitogen-activated protein kinase (MAPK) signaling pathway, phosphatidylinositol signaling system, and plant hormone signal transduction pathways etc. In addition, some transcription factor families, such as MYB, WRKY, and NAC, were also activated by exogenous MT treatment under salt stress. The results suggest that MT can improve the tolerance of sour jujube to salt stress mainly through the regulation of MAPK, hormone signaling pathways, and related transcription factors, which could lay the foundation for further study on the molecular mechanisms of how exogenous MT regulates salt stress tolerance in sour jujube.

Keywords

• sour jujube
• melatonin
• salt stress
• transcriptome
• mapk
• hormones