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Overexpression of TaNHX3, a Vacuolar Na⁺/H⁺ Antiporter Gene in Wheat, Enhances Salt Stress Tolerance in Tobacco by Improving Related Physiological Processes

Wenjing Lu, Chengjin Guo, Xiaojuan Li, Weiwei Duan, Chunying Ma, Miao Zhao, Juntao Gu, Xiaoming Du, Zhuling Liu, Kai Xiao

Plant Physiol Biochem. 2014 Mar;76:17-28.

PMID: 24448321

Abstract:

Salt stress is one of the major abiotic stresses affecting plant growth, development, and productivity. In this study, we functionally characterized a wheat vacuolar Na(+)/H(+) antiporter gene (TaNHX3). TaNHX3 is 78.9% identical with TaNHX2 in nucleic acid level, encoding a polypeptide of 522 amino acids (aa). TaNHX3 is targeted onto tonoplast after ER sorting and can complement the growth under salt stress in a yeast mutant with a defective vacuolar Na(+)/H(+) antiporter exchange. TaNHX3 transcripts were induced by applying salt stress in wheat cultivars. More TaNHX3 were detected in the salt-stress-resistant cultivar Ji 7369 compared with the salt-stress-sensitive cultivar Shimai 12 and Ji-Shi-3, an isogenic line derived from aforementioned cultivars with Shimai 12 genetic background. The ectopic TaNHX3 expression in tobacco significantly enhanced the plant tolerance to salt stress. Compared with control plants, the TaNHX3 overexpressing plants displayed no varied Na(+) contents and accumulated more Na(+) amount in plants. However, they exhibited higher fresh and dry weights, more accumulative nitrogen, phosphorus, and potassium, higher contents of chlorophyll, carotenoid, soluble protein, higher activities of the antioxidant enzymes including superoxide dismutase, catalase, and peroxidase, and lower malondialdehyde and H2O2 amount. Our results indicated that TaNHX3 plays an important role in regulating the cytosolic Na(+) transportation within vacuoles under high salinity, alleviating the Na(+) damage effects. The improved salt stress tolerance in TaNHX3 overexpressing tobacco plants is closely associated with the improvement of the aforementioned physiological processes. TaNHX3 can be used as a candidate gene for molecular breeding of salt-tolerant plants.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
IAR42418014 Fluorescent Na+ indicator, 522 Fluorescent Na+ indicator, 522 Price
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