Physiological adaptation and gene expression analysis of Casuarina equisetifolia under salt stress

作者：Fan, C.; Qiu, Z.; Zeng, B.^*; Li, X.; Xu, S. H.

来源：Biologia Plantarum, 2018, 62(3): 489-500.

DOI：10.1007/s10535-018-0799-y

• antiporter genes
• catalase
• glutathione peroxidase
• ion homeostasis
• potassium
• salt overly sensitive
• sodium
• superoxide dismutase

Casuarina equisetifolia is widely planted in coastal areas of tropical and subtropical regions as windbreaks or to stabilize dunes against wind erosion due to its high salt tolerance and nitrogen-fixing ability. To investigate the mechanisms responsible for its salt tolerance, we examined growth, mineral composition, expression of genes for sodium (Na+) and potassium (K+) transport proteins, and antioxidant responses under NaCl treatments. Increasing NaCl concentrations inhibited lateral root elongation and decreased plant height, length of internodes, and numbers of branches and twigs. The Na+ content significantly increased whereas the K+ content significantly decreased in both shoots and roots with increasing external NaCl concentration, resulting in a significant increase in Na+/K+ ratio. Most of the Na+/H+ antiporter genes (NHXs) were obviously upregulated in roots after 24 and 168 h of salt stress, and NHX7 was especially induced after 168 h. Almost all salt overly sensitive (SOS) genes were induced after 168-h treatment. Additionally, activities of superoxide dismutase, glutathione peroxidase, and catalase were significantly changed in shoots and roots under salt stress. Hence, we conclude that salinity tolerance of C. equisetifolia mainly relied on sequestering excess Na+ into vacuoles and on induced expression of NHX and SOS genes in roots and thus the maintenance of sufficient K+ content in shoots.

• 出版日期2018-9
• 单位中国林业科学研究院热带林业研究所; 中国林业科学研究院