School of Plant Sciences, University of Arizona, Tucson, Arizona 85721.
School of Plant Sciences, University of Arizona, Tucson, Arizona 85721
Plant Physiol. 2019 Mar;179(3):1176-1192. doi: 10.1104/pp.18.01400. Epub 2019 Jan 3.
The SALT-OVERLY-SENSITIVE (SOS) pathway in Arabidopsis () functions to prevent the toxic accumulation of sodium in the cytosol when plants are grown in salt-affected soils. In this pathway, the CALCINEURIN B-LIKE10 (AtCBL10) calcium sensor interacts with the AtSOS2 kinase to activate the AtSOS1 plasma membrane sodium/proton exchanger. has been duplicated in Eutrema (), a salt-tolerant relative of Arabidopsis. Because Eutrema maintains growth in salt-affected soils that kill most crop plants, the duplication of provides a unique opportunity to functionally test the outcome of gene duplication and its link to plant salt tolerance. In Eutrema, individual down-regulation of the duplicated genes ( and ) decreased growth in the presence of salt and, in combination, led to an even greater decrease, suggesting that both genes function in response to salt and have distinct functions. Cross-species complementation assays demonstrated that has an enhanced ability to activate the SOS pathway while has a function not performed by or Chimeric EsCBL10a/EsCBL10b proteins revealed that the specific functions of the EsCBL10 proteins resulted from changes in the amino terminus. The duplication of increased calcium-mediated signaling capacity in Eutrema and conferred increased salt tolerance to salt-sensitive Arabidopsis.
拟南芥中的盐过度敏感（SOS）途径在植物生长在受盐影响的土壤中时，可防止细胞质中钠的毒性积累。在该途径中，钙调神经磷酸酶 B 类似蛋白 10（AtCBL10）与 SOS2 激酶相互作用，激活 SOS1 质膜钠/质子交换器。在拟南芥的耐盐相关物种盐芥（Eutrema）中， 被复制。由于盐芥在杀死大多数作物植物的受盐影响的土壤中保持生长， 的复制为功能测试基因复制的结果及其与植物耐盐性的联系提供了独特的机会。在盐芥中，单个下调复制的 基因（ 和 ）会降低盐存在下的生长，而组合下调则导致生长进一步下降，这表明这两个基因都能响应盐并具有不同的功能。种间互补测定表明， 在激活 SOS 途径方面具有增强的能力，而 在 或 不具有的功能。嵌合 EsCBL10a/EsCBL10b 蛋白揭示了 EsCBL10 蛋白的特定功能是由于其氨基末端的变化所致。 在盐芥中增加了钙介导的信号转导能力，并赋予了对盐敏感的拟南芥更高的耐盐性。
