Identification of up-regulated genes provides integrated insight into salt-induced tolerance mechanisms in Sesuvium portulacastrum roots

Abstract

Sesuvium portulacastrum, a promising facultative halophyte species, has a remarkable ability to survival at severe salt of ~1000 mM NaCl. However, genes encoding proteins involved in the process of salt tolerance in S. portulacastrum are limited. In this study, suppression subtractive hybridization together with reverse northern blot analysis and RT-PCR was used to identify up-regulated genes in roots after treatment with seawater for 2–24 h. We identified a total of 148 unigenes, and most of these genes were predominantly associated with ‘signal transduction and transcription’, ‘stress/defense response’, ‘transport’ and ‘metabolism’. Comparative analysis between physiological response and differentially expressed genes highlighted that sodium (Na+) transport, compartmentation, reactive oxygen species (ROS) scavenging, and sugar-metabolizing regulation play important roles in salt tolerance of S. portulacastrum, whereas inhibition of root elongation induced by high salinity may be related to lignin deposition and disruption of calcium homeostasis.