Calcium regulation of sodium hypersensitivities of sos3 and athkt1 mutants
Calcium regulation of sodium hypersensitivities of sos3 and athkt1 mutants
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DOI：
10.1093/pcp/pcj029
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发表时间：
2006-05-01
影响因子：
4.9
通讯作者：
Schroeder, Julian I.
中科院分区：
文献类型：
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作者：
Horie, Tomoaki;Horie, Rie;Schroeder, Julian I.
AtHKT 1基因中的T-DNA破坏突变先前已被证明可以抑制sos 3突变体的盐敏感性。然而，sos 3和athkt 1单突变体均显示钠（Na+）超敏反应。在本研究中，我们进一步分析了潜在的机制，这些非加性和抵消Na+敏感性的特点athkt 1 -1 sos 3和athkt 1 -2 sos 3双突变体植物。出乎意料的是，在土壤中生长的成熟的双突变体植物清楚地显示出增加的Na+敏感性相比，野生型植物，当植物受到盐胁迫。athkt 1 sos 3双突变体植株的盐敏感表型与athkt 1植株相似，表现为叶和茎的失绿。土壤中生长的athkt 1 sos 3双突变体和athkt 1单突变体植物的木质部汁液样品中的Na+含量表现出显着的Na+过量积累响应于盐胁迫。盐胁迫分析，使用基本的最低营养培养基和Murashige-Skoog（MS）培养基显示，athkt 1 sos 3双突变体植物表现出更多的athkt 1单music样的表型在3 mM的外部Ca 2+的存在下，但表现出更多的sos 3单music样的表型在1 mM的外部Ca 2+的存在下。综合多项分析表明，外部Ca 2+浓度强烈影响的Na+胁迫响应的athkt 1 sos 3双突变体。此外，所提出的研究结果表明，SOS 3和AtHKT 1是生理上不同的耐盐性的主要决定因素，使SOS 3更强烈地导致Na+在根中的过度积累，而athkt 1导致Na+水平的增加，在木质部汁液和芽和伴随的Na+减少根。
T-DNA disruption mutations in the AtHKT1 gene have previously been shown to suppress the salt sensitivity of the sos3 mutant. However, both sos3 and athkt1 single mutants show sodium (Na+) hypersensitivity. In the present study we further analyzed the underlying mechanisms for these nonadditive and counteracting Na+ sensitivities by characterizing athkt1-1 sos3 and athkt1-2 sos3 double mutant plants. Unexpectedly, mature double mutant plants grown in soil clearly showed an increased Na+ hypersensitivity compared with wild-type plants when plants were subjected to salinity stress. The salt sensitive phenotype of athkt1 sos3 double mutant plants was similar to that of athkt1 plants, which showed chlorosis in leaves and stems. The Na+ content in xylem sap samples of soil-grown athkt1 sos3 double and athkt1 single mutant plants showed dramatic Na+ over-accumulation in response to salinity stress. Salinity stress analyses using basic minimal nutrient medium and Murashige-Skoog (MS) medium revealed that athkt1 sos3 double mutant plants show a more athkt1 single mutant-like phenotype in the presence of 3 mM external Ca2+, but show a more sos3 single mutant-like phenotype in the presence of 1 mM external Ca2+. Taken together multiple analyses demonstrate that the external Ca2+ concentration strongly impacts the Na+ stress response of athkt1 sos3 double mutants. Furthermore, the presented findings show that SOS3 and AtHKT1 are physiologically distinct major determinants of salinity resistance such that sos3 more strongly causes Na+ overaccumulation in roots, whereas athkt1 causes an increase in Na+ levels in the xylem sap and shoots and a concomitant Na+ reduction in roots.