Physiological adaptation and gene expression analysis of Casuarina equisetifolia under salt stress
Physiological adaptation and gene expression analysis of Casuarina equisetifolia under salt stress
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DOI：
10.1007/s10535-018-0799-y
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发表时间：
2018-09-01
影响因子：
1.5
通讯作者：
Xu, S. H.
中科院分区：
文献类型：
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作者：
Fan, C.;Qiu, Z.;Xu, S. H.
木麻黄因其高耐盐性和固氮能力而广泛种植在热带和亚热带沿海地区，作为防风林或稳定沙丘以防止风蚀。为了研究其耐盐性的机制，我们检测了生长、矿物质成分、钠 (Na+) 和钾 (K+) 转运蛋白基因的表达，以及 NaCl 处理下的抗氧化反应。增加氯化钠浓度会抑制侧根伸长，降低株高、节间长度以及分枝和小枝的数量。随着外部 NaCl 浓度的增加，地上部和根部的 Na+ 含量显着增加，而 K+ 含量显着降低，导致 Na+/K+ 比值显着增加。盐胁迫24和168小时后，根中大多数Na+/H+逆向转运蛋白基因（NHXs）明显上调，其中NHX7在168小时后表达尤为明显。几乎所有的盐过度敏感（SOS）基因在 168 小时处理后均被诱导。此外，盐胁迫下芽和根中超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶的活性显着变化。因此，我们得出结论，木贼的耐盐性主要依赖于将过量的Na+封存在液泡中以及诱导根部NHX和SOS基因的表达，从而维持地上部足够的K+含量。
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.