Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Plant Genetic Engineering Center of Hebei Province, Shijiazhuang, 050051, China,
Plant Mol Biol. 2015 Feb;87(3):317-27. doi: 10.1007/s11103-014-0278-6. Epub 2014 Dec 31.
Previous studies have shown that TaNHX2 transgenic alfalfa (Medicago sativa L.) accumulated more K(+) and less Na(+) in leaves than did the wild-type plants. To investigate whether the increased K(+) accumulation in transgenic plants is attributed to TaNHX2 gene expression and whether the compartmentalization of Na(+) into vacuoles or the intracellular compartmentalization of potassium is the critical mechanism for TaNHX2-dependent salt tolerance in transgenic alfalfa, aerated hydroponic culture was performed under three different stress conditions: control condition (0.1 mM Na(+) and 6 mM K(+) inside culture solution), K(+)-sufficient salt stress (100 mM NaCl and 6 mM K(+)) and K(+)-insufficient salt stress (100 mM NaCl and 0.1 mM K(+)). The transgenic alfalfa plants had lower K(+) efflux through specific K(+) channels and higher K(+) absorption through high-affinity K(+) transporters than did the wild-type plants. Therefore, the transgenic plants had greater K(+) contents and [K(+)]/[Na(+)] ratios in leaf tissue and cell sap. The intracellular compartmentalization of potassium is critical for TaNHX2-induced salt tolerance in transgenic alfalfa.
先前的研究表明，转 TaNHX2 苜蓿（Medicago sativa L.）叶片中积累的 K+多于野生型，而 Na+则少于野生型。为了研究转基因植物中 K+积累的增加是否归因于 TaNHX2 基因的表达，以及 Na+是否被区室化为液泡或细胞内区室化的钾，在三种不同的胁迫条件下进行了充气水培培养：对照条件（培养液中 0.1 mM Na+和 6 mM K+）、K+充足盐胁迫（100 mM NaCl 和 6 mM K+）和 K+不足盐胁迫（100 mM NaCl 和 0.1 mM K+）。与野生型相比，转 TaNHX2 苜蓿植物通过特定的 K+通道的 K+外排率较低，通过高亲和力 K+转运体的 K+吸收率较高。因此，转基因植物叶片组织和细胞汁液中的 K+含量和[K+]/[Na+]比值更高。细胞内钾的区室化对转 TaNHX2 苜蓿的耐盐性至关重要。
