Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Straße 24-25, Haus 20, 14476, Potsdam-Golm, Germany.
New Phytol. 2020 Feb;225(4):1681-1698. doi: 10.1111/nph.16247. Epub 2019 Nov 11.
Salinity stress limits plant growth and has a major impact on agricultural productivity. Here, we identify NAC transcription factor SlTAF1 as a regulator of salt tolerance in cultivated tomato (Solanum lycopersicum). While overexpression of SlTAF1 improves salinity tolerance compared with wild-type, lowering SlTAF1 expression causes stronger salinity-induced damage. Under salt stress, shoots of SlTAF1 knockdown plants accumulate more toxic Na ions, while SlTAF1 overexpressors accumulate less ions, in accordance with an altered expression of the Na transporter genes SlHKT1;1 and SlHKT1;2. Furthermore, stomatal conductance and pore area are increased in SlTAF1 knockdown plants during salinity stress, but decreased in SlTAF1 overexpressors. We identified stress-related transcription factor, abscisic acid metabolism and defence-related genes as potential direct targets of SlTAF1, correlating it with reactive oxygen species scavenging capacity and changes in hormonal response. Salinity-induced changes in tricarboxylic acid cycle intermediates and amino acids are more pronounced in SlTAF1 knockdown than wild-type plants, but less so in SlTAF1 overexpressors. The osmoprotectant proline accumulates more in SlTAF1 overexpressors than knockdown plants. In summary, SlTAF1 controls the tomato's response to salinity stress by combating both osmotic stress and ion toxicity, highlighting this gene as a promising candidate for the future breeding of stress-tolerant crops.
盐胁迫限制植物生长，对农业生产力有重大影响。在这里，我们鉴定出 NAC 转录因子 SlTAF1 是栽培番茄（Solanum lycopersicum）耐盐性的调节剂。虽然过表达 SlTAF1 与野生型相比提高了耐盐性，但降低 SlTAF1 的表达会导致更强的盐诱导损伤。在盐胁迫下，SlTAF1 敲低植物的枝条积累更多的有毒 Na 离子，而 SlTAF1 过表达植株则积累较少的离子，这与 Na 转运基因 SlHKT1;1 和 SlHKT1;2 的表达改变一致。此外，SlTAF1 敲低植物在盐胁迫期间气孔导度和孔面积增加，但 SlTAF1 过表达植株减少。我们鉴定出应激相关转录因子、脱落酸代谢和防御相关基因是 SlTAF1 的潜在直接靶标，这与其与活性氧清除能力和激素反应变化相关。盐胁迫诱导的三羧酸循环中间体和氨基酸变化在 SlTAF1 敲低植物中比野生型植物更为明显，但在 SlTAF1 过表达植株中则不那么明显。渗透调节剂脯氨酸在 SlTAF1 过表达植株中的积累量多于敲低植株。总之，SlTAF1 通过对抗渗透胁迫和离子毒性来控制番茄对盐胁迫的反应，突出了该基因作为未来培育耐盐作物的有前途的候选基因。
