Institute for Life and Earth Sciences, School of Energy, Geosciences, Infrastructure and Society, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK.
Plant Physiol Biochem. 2019 Sep;142:246-253. doi: 10.1016/j.plaphy.2019.07.014. Epub 2019 Jul 10.
Transcription factors such as MYB have previously been associated with the plant response to drought. In this work, studies on the function of the barley (Hordeum vulgare L.) transcription factor HvMYB1 show that gene expression is upregulated in wildtype barley roots and leaves under drought and osmotic stress. Transgenic barley plants that overexpress HvMYB1 were found to be more resistant to drought, showing enhanced relative water content and reduced water loss rate and stomatal conductance as compared to control plants. Levels of the osmolyte proline were enhanced as was expression of dehydrin HvDNH6 in the transgenic lines under drought conditions. The levels of the reactive oxygen species HO were enhanced in wildtype roots and leaves by drought, but less so in the HvMYB1 overexpressing lines. Enzyme activity of the low affinity HO degrading enzyme catalase (EC 1.11.1.6) was also lower in droughted HvMYB1 overexpressing lines. Gene expression of the high affinity ROS scavengers ASCORBATE PEROXIDASE and GLUTATHIONE PEROXIDASE was found to be constitutively high in the overexpressing lines, whereas CATALASE gene expression was similar to the control plants. These results suggest a role for HvMYB1 in protecting plants against drought in the vegetative plant by acting as a mediator of abscisic acid action.
转录因子如 MYB 先前已被认为与植物对干旱的反应有关。在这项工作中，对大麦（Hordeum vulgare L.）转录因子 HvMYB1 功能的研究表明，在野生型大麦根和叶中，基因表达在干旱和渗透胁迫下上调。过表达 HvMYB1 的转基因大麦植物对干旱更具抗性，与对照植物相比，表现出相对较高的水分含量、较低的水分损失率和气孔导度。在干旱条件下，渗透胁迫的转基因系中脯氨酸等渗透物的水平和脱水素 HvDNH6 的表达增强。在野生型根和叶中，干旱增强了活性氧物种 HO 的水平，但在 HvMYB1 过表达系中则不然。低亲和力 HO 降解酶过氧化氢酶（EC 1.11.1.6）的酶活性在干旱的 HvMYB1 过表达系中也较低。高亲和力 ROS 清除剂 ASCORBATE PEROXIDASE 和 GLUTATHIONE PEROXIDASE 的基因表达在过表达系中持续较高，而 CATALASE 基因表达与对照植物相似。这些结果表明，HvMYB1 在保护植物免受营养植物干旱中的作用是作为脱落酸作用的介质。
