Recent Progress on the Salt Tolerance Mechanisms and Application of Tamarisk

et al. 2022

IJMS

Soil salinization is one of the main environmental factors affecting plant growth worldwide. Tamarix ramosissima Ledeb. (T. ramosissima) is a halophyte representative that is widely grown in salinized soils. As an important nutrient element for plant growth, K+ plays an important role in improving the tolerance to salt stress, but the mechanism of reducing the damage caused by NaCl stress to T. ramosissima is less reported. Our results show that the proline content and the Log2 fold-change of proline’s relative quantification in the roots of T. ramosissima increased over time with the application of exogenous potassium (K+) for 48 h and 168 h under NaCl stress. Moreover, 13 amino-acid-related metabolic pathways were involved in the resistance of T. ramosissima to salt stress. Mainly, the aldehyde dehydrogenase family genes and tryptophan-synthase-related genes were found at 48 h and 168 h with exogenous potassium applied to the roots of T. ramosissima under NaCl stress, and they regulated their related metabolic accumulation in the arginine and proline metabolism pathways, increasing the effectiveness of inducing NaCl tolerance of T. ramosissima. It is noteworthy that alpha-ketobutyric was produced in the roots of T. ramosissima under NaCl stress for 48 h with the application of exogenous potassium, which is one of the most effective mechanisms for inducing salt tolerance in plants. Meanwhile, we found three DEGs regulating alpha-ketobutyric acid. This study provides a scientific theoretical basis for further understanding the molecular mechanism of K+ alleviating the salinity damage to T. ramosissima caused by NaCl.

Section: Introductionmentioning

confidence: 99%

Analysis of Amino Acids in the Roots of Tamarix ramosissima by Application of Exogenous Potassium (K+) under NaCl Stress

et al. 2022

IJMS

“…Halophytes are highly salt-tolerant plants that can complete their life cycle at ≥200 mM NaCl concentration [ 41 ]. Tamarix plants are halophilic plants [ 42 ], they are able to avoid salt damage by secreting salt through the salt glands [ 43 , 44 ], and the use of physiological and metabolic processes to enhance tolerance [ 45 , 46 , 47 ], such as osmoregulation, free radical scavenging, cellular detoxification and protection of biological macromolecules [ 48 ]. T. ramosissima , a member of the genus Tamarix plants, is widely grown in saline soils [ 49 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of Exogenous (K+) Potassium Application on Plant Hormones in the Roots of Tamarix ramosissima under NaCl Stress

et al. 2022

Genes

Abiotic stresses such as salt stress seriously affect the growth and yield of plants. Tamarix ramosissima Lcdcb (T. ramosissima) is a widely cultivated halophyte in saline-alkali areas of the world. As an essential element for plant growth and development, K+ plays an irreplaceable role in improving the tolerance of plants to salt stress. However, there are few reports on the mechanism of K+ in promoting plant hormones to reduce the damage of NaCl stress to T. ramosissima. In this study, we sequenced the transcriptome of the roots of T. ramosissima which were treated with exogenous potassium (K+) for 0 h, 48 h and 168 h under NaCl stress, according to the changes in the expression levels of differentially expressed genes (DEGs) in T. ramosissima roots. Key candidate genes and metabolic pathways related to plant hormones were mined for analysis and further verified by quantitative real-time PCR (qRT-PCR). The results showed that under NaCl stress for 48 h and 168 h, there were a large number of DEGs in the roots of T. ramosissima, and the expression levels changed over time. In particular, we found that 56 plant hormone-related genes were annotated to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and with the increase of time, their expression levels were mainly up-regulated and involved in the related metabolic pathways to resist NaCl stress. It is worth noting that 7 DEGs related to abscisic acid (ABA), 28 DEGs related to auxin, 1 DEG related to ethylene (ET), and 1 DEG related to cytokinin (CK) were added within 168 h of exogenous potassium, and they were involved in alleviating the root damage of T. ramosissima under NaCl stress and played an important role. In addition, we found the plant hormone signal transduction pathway, which plays an important role in resistance to NaCl stress. As a result of this study, the molecular mechanism of plant hormones involved in applying exogenous potassium under NaCl stress is further understood, resulting in a better understanding of how exogenous potassium can alleviate the damage caused by NaCl under stress in T. ramosissima.

“…The enzymatic system mainly includes enzyme systems, including superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbic acid peroxidase (APX), glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST), monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR) [ 12 , 13 ]. Under salt stress, the increased activity of these antioxidant enzymes can generally be considered to enhance plant salt tolerance [ 14 ]. Nonenzymatic systems include ascorbic acid (AsA), glutathione (GSH), α-tocopherol, phenolic compounds (PhOH), flavonoids, alkaloids, and nonprotein amino acids [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to their antioxidant, anti-inflammatory, and anticancer properties, Tamarix plants are rich in flavonoids and phenols. Tamarix plants are widely used in the treatment of diabetes, rheumatoid arthritis, Alzheimer’s disease, and cancer, and in liver protection [ 14 ]. Tamarix ramosissima Ledeb ( T .…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Antioxidant Mechanism of Tamarix ramosissima Roots under NaCl Stress Based on Physiology, Transcriptomic and Metabolomic

et al. 2022

Antioxidants

There is a serious problem with soil salinization that affects the growth and development of plants. Tamarix ramosissima Ledeb (T. ramosissima), as a halophyte, is widely used for afforestation in salinized soils. At present, there are few reports on the antioxidant mechanism of T. ramosissima under NaCl stress. In this study, we learned about the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) content changes in T. ramosissima. We also mined the relevant metabolic pathways in the antioxidant mechanism, candidate key genes, and their related differential metabolites and verified them using quantitative real-time PCR (qRT-PCR). The results show that the SOD, POD, and CAT activities, and the H2O2 and MDA content reached the highest values in the roots of T. ramosissima. Simultaneously, 92 differentially expressed genes (DEGs) related to antioxidant enzyme activities changed during 48 and 168 h of NaCl stress, and these DEGs were mainly upregulated in 168 h. Based on the association analysis of transcriptomic and metabolomic data, we found Unigene0089358 and Unigene0007782 as genes related to key enzymes in the flavonoid biosynthesis pathway. They were located in the upstream positive regulation at 48 and 168 h under NaCl stress, and their respective related metabolites (phloretin and pinocembrin) were involved in resistance to NaCl stress, and they were significantly correlated with their respective metabolites. In conclusion, at 48 and 168 h under NaCl stress, the roots of T. ramosissima resist NaCl stress by enhancing enzymatic and nonenzymatic antioxidant mechanisms, scavenging ROS generated by high-salt stress, alleviating NaCl toxicity, and maintaining the growth of T. ramosissima. This study provides genetic resources and a scientific theoretical basis for further breeding of salt-tolerant Tamarix plants and the molecular mechanism of antioxidants to alleviate NaCl toxicity.