Effects of Salinity on Metabolic Profiles, Gene Expressions, and Antioxidant Enzymes in Halophyte Suaeda salsa

Abstract

Halophyte Suaeda salsa is native to the saline soil in the Yellow River Delta. Soil salinity can reduce plant productivity and therefore is the most important factor for the degradation of wetlands in the Yellow River Delta. In this work we characterized the salinity-induced effects in S. salsa in terms of metabolic profiling, antioxidant enzyme activities, and gene expression quantification. Our results showed that salinity inhibited plant growth of S. salsa and upregulated gene expression levels of myo-inositol-1-phosphate synthase (INPS), choline monooxygenase (CMO), betaine aldehyde dehydrogenase (BADH), and catalase (CAT), and elevated the activities of superoxide dismutase (SOD), peroxidase (POD), CAT, and glutathione peroxidase (GPx). The significant metabolic responses included the depleted amino acids malate, fumarate, choline, phosphocholine, and elevated betaine and allantoin in the aboveground part of S. salsa seedlings as well as depleted glucose and fructose and elevated proline, citrate, and sucrose in root tissues. Based on these significant biological markers, salinity treatments induced clear osmotic stress (for example, INPS, CMO, BADH, betaine, proline) and oxidative stress (for example, SOD, POD, CAT, GPx activities), disturbed protein biosynthesis/degradation (amino acids and total protein) and energy metabolism (for example, glucose, sucrose, citrate) in S. salsa.

Toxicological effects of environmentally relevant lead and zinc in halophyte Suaeda salsa by NMR-based metabolomics

“…For the above-ground part of S. salsa seedlings, decreased intermediates, succinate and fumarate, in tricarboxylic acid (TCA) cycle showed the disturbances in TCA cycle that is related to energy metabolism (Zhang et al, 2011). The increased amino acids and decreased total protein suggested that protein biodegradation was enhanced in S. salsa caused by Hg treatment (Wu et al, 2012;Dai et al, 2010). In plant cells, sugars such as glucose, fructose and sucrose, are commonly derived from photosynthesis and gluconeogenesis.…”

“…In plant cells, sugars such as glucose, fructose and sucrose, are commonly derived from photosynthesis and gluconeogenesis. Hereby, decreased glucose might imply that photosynthesis and/or gluconeogenesis were/was inhibited by Hg exposure in S. salsa (Wu et al, 2012). Ferulate is one of the phenolic acids in plants, occurring in seeds and leaves (Mathew and Abraham, 2004).…”

Integrated proteomics and metabolomics for dissecting the mechanism of global responses to salt and alkali stress in Suaeda corniculata

“…Extraction analysis of S. corniculata leaf tissue was performed with a Bruker AV 500 NMR spectrometer at 500.18 MHz (at 298 K) (Wu et al 2012). One dimensional (1D) 1 H NMR spectra were obtained with the following parameters: 11.9 μs pulse, 6009.6 Hz spectral width, 0.1 s mixing time, and 3.0 s relaxation delay with standard 1D NOESY pulse sequence, with 128 transients collected into 16,384 data points.…”

“…More than twenty species of Suaeda have been reported for their ability to survive high salt conditions, including S. salsa (Zhang and Zhao 1998), S. maritima (Maathuis et al 1992;Wetson and Flowers 2010), S. aegyptiaca (Askari et al 2006), S. asparagoides (Ayarpadikannan et al 2012), S. fruticosa (Khan and Ungar 1998), S. glauca (Yang et al 2008b, S. physophora (Song et al 2006) and S. corniculata (Wei et al 2012). In particular, recent studies of salt responsive physiology, molecular genetics, proteomics and metabolomics in S. salsa have yielded more information for understanding the complex mechanisms of Suaeda plants' salt response and tolerance (Zhang et al 2001;Lu et al 2003;Pang et al 2005;Han et al 2011;Li et al 2011Li et al , 2011bWu et al 2012). In previous studies of S. salsa, salt treatment caused the up-regulation of aquaporin (Qi et al 2009), vacuolar Na + /H + antiporter (Qiu et al 2007), V-ATPase and V-PPase , indicating that Suaeda can maintain homeostasis in water potential and ion distribution by increasing leaf succulence and compartmenting the ions.…”

“…In previous studies of S. salsa, salt treatment caused the up-regulation of aquaporin (Qi et al 2009), vacuolar Na + /H + antiporter (Qiu et al 2007), V-ATPase and V-PPase , indicating that Suaeda can maintain homeostasis in water potential and ion distribution by increasing leaf succulence and compartmenting the ions. The choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH) genes in S. salsa which encode the enzymes involved in the synthesis of osmolytes were up-regulated under salt stress, suggesting that Suaeda plants could enhance their resistance to the osmotic stress by the accumulation of osmolytes when subjected to salt stress (Wu et al 2012). In addition, salt stress accelerates the production of reactive oxygen species (ROS) in plant cells (Zhu 2001), and halophytes such as Suaeda species can maintain the balance between formation and removal of ROS by increasing the activity of antioxidant enzyme such as SOD (Wang et al 2004;Guan et al 2011), APX (Pang et al 2005), GPX (Wu et al 2012), and CAT (Pang et al 2005;Wu et al 2012).…”