The Australian Centre for Plant Functional Genomics and the University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia.
Plant Cell Environ. 2010 May;33(5):793-804. doi: 10.1111/j.1365-3040.2009.02105.x. Epub 2010 Feb 5.
Salinity tolerance can be attributed to three different mechanisms: Na+ exclusion from the shoot, Na+ tissue tolerance and osmotic tolerance. Although several key ion channels and transporters involved in these processes are known, the variation in expression profiles and the effects of these proteins on Na+ transport in different accessions of the same species are unknown. Here, expression profiles of the genes AtHKT1;1, AtSOS1, AtNHX1 and AtAVP1 are determined in four ecotypes of Arabidopsis thaliana. Not only are these genes differentially regulated between ecotypes, the expression levels of the genes can be linked to the concentration of Na+ in the plant. An inverse relationship was found between AtSOS1 expression in the root and total plant Na+ accumulation, supporting a role for AtSOS1 in Na+ efflux from the plant. Similarly, ecotypes with high expression levels of AtHKT1;1 in the root had lower shoot Na+ concentrations, due to the hypothesized role of AtHKT1;1 in retrieval of Na+ from the transpiration stream. The inverse relationship between shoot Na+ concentration and salinity tolerance typical of most cereal crop plants was not demonstrated, but a positive relationship was found between salt tolerance and levels of AtAVP1 expression, which may be related to tissue tolerance.
从地上部分排除 Na+、Na+组织耐受性和渗透耐受性。尽管已知有几个参与这些过程的关键离子通道和转运蛋白，但这些蛋白在同一物种的不同品系中的表达谱变化及其对 Na+运输的影响尚不清楚。在这里，确定了拟南芥四个生态型中 AtHKT1;1、AtSOS1、AtNHX1 和 AtAVP1 基因的表达谱。这些基因不仅在生态型之间存在差异调节，而且基因的表达水平可以与植物中 Na+的浓度相关联。在根中发现 AtSOS1 表达与植物总 Na+积累之间存在负相关关系，这支持了 AtSOS1 在 Na+从植物中排出的作用。同样，根中 AtHKT1;1 表达水平高的生态型地上部分 Na+浓度较低，这是由于假设 AtHKT1;1 在从蒸腾流中回收 Na+方面的作用。大多数谷类作物植物典型的地上部分 Na+浓度与耐盐性之间的负相关关系没有得到证明，但发现耐盐性与 AtAVP1 表达水平之间存在正相关关系，这可能与组织耐受性有关。
