National Technique Innovation Center for Regional Wheat Production, Key Laboratory of Crop Ecophysiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China.
National Technique Innovation Center for Regional Wheat Production, Key Laboratory of Crop Ecophysiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China.
Plant Physiol Biochem. 2023 Jul;200:107769. doi: 10.1016/j.plaphy.2023.107769. Epub 2023 May 16.
Drought priming is a promising strategy to enhance tolerance to recurred drought in wheat. However, the underlying mechanisms of priming-induced tolerance are far from clear. Here, three different priming intensities (P1D, P2D, P3D) and two varieties with different sensitivities to drought priming were used to investigate the effects and mechanisms of drought priming. Results showed light (P1D) or moderate (P2D) drought priming intensity induced positive effects for the drought sensitive variety (YM16), while high (P3D) priming intensity brought a negative impact on the plant drought resistant. For drought insensitive one (XM33), light priming intensity had no significant effect on tolerance to drought, while moderate or high intensity showed better priming effects. Moderate priming induced higher leaf water potential and also the osmolytes levels. Consistent with the proline and betaine, the related synthetic enzymatic activities, as well as the expression of TaP5CS and TaBADH were higher in P2D in YM16 and P3D in XM33. The contents of proline and betaine showed a positive correlation with activities of SOD, CAT, GR, AsA, and GSH contents, and a negative correlation with O, HO, and MDA contents. Further analysis revealed CG demethylation of ATG-proximal regions in the promoter of TaP5CS and TaBADH were involved in promoting the synthesis of proline and betaine in primed plants. Collectively, these findings demonstrate drought priming effect was variety independent but depended on the priming severity, and demethylation of TaP5CS and TaBADH involved in the accumulation of osmolytes which contribute to the enhanced drought tolerance induced by priming.
干旱引发是提高小麦对反复干旱耐性的一种很有前途的策略。然而，引发诱导耐性的潜在机制尚不清楚。在这里，使用了三种不同的引发强度（P1D、P2D、P3D）和两个对干旱引发敏感程度不同的品种，研究了干旱引发的效果和机制。结果表明，轻度（P1D）或中度（P2D）干旱引发强度对敏感品种（YM16）产生了积极的影响，而高强度（P3D）引发强度对植物抗旱性产生了负面影响。对于不敏感品种（XM33），轻度引发强度对耐旱性没有显著影响，而中度或高强度显示出更好的引发效果。中度引发诱导更高的叶片水势和渗透调节物质水平。与脯氨酸和甜菜碱一致，相关合成酶活性以及 TaP5CS 和 TaBADH 的表达在 YM16 的 P2D 和 XM33 的 P3D 中更高。脯氨酸和甜菜碱的含量与 SOD、CAT、GR、AsA 和 GSH 含量的活性呈正相关，与 O、HO 和 MDA 含量呈负相关。进一步的分析表明，TaP5CS 和 TaBADH 启动子中 ATG 近端区域的 CG 去甲基化参与了引发植物中脯氨酸和甜菜碱的合成。总的来说，这些发现表明干旱引发的效果是品种独立的，但取决于引发的严重程度，并且 TaP5CS 和 TaBADH 的去甲基化参与了渗透调节物质的积累，这有助于引发诱导的耐旱性增强。
