State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, 271018, People's Republic of China.
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Huanghuai Region), Ministry of Agriculture, Tai'an, 271018, People's Republic of China.
BMC Plant Biol. 2018 Dec 14;18(1):355. doi: 10.1186/s12870-018-1592-y.
Plant phospholipase D (PLD), which can hydrolyze membrane phospholipids to produce phosphatidic acid (PA), a secondary signaling molecule, has been proposed to function in diverse plant stress responses. Both PLD and PA play key roles in plant growth, development, and cellular processes. PLD was suggested to mediate the regulation of stomatal movements by abscisic acid (ABA) as a response to water deficit. In this research, we characterized the roles of the cucumber phospholipase D alpha gene (CsPLDα, GenBank accession number EF363796) in the growth and tolerance of transgenic tobacco (Nicotiana tabacum) to drought stress.
The CsPLDα overexpression in tobacco lines correlated with the ABA synthesis and metabolism, regulated the rapid stomatal closure in drought stress, and reduced the water loss. The NtNCED1 expression levels in the transgenic lines and wild type (WT) were sharply up-regulated after 16 days of drought stress compared with those before treatment, and the expression level in the transgenic lines was significantly higher than that in the WT. The NtAOG expression level evidently improved after 8 and 16 days compared with that at 0 day of treatment and was significantly lower in the transgenic lines than in the WT. The ABA content in the transgenic lines was significantly higher than that in the WT. The CsPLDα overexpression could increase the osmolyte content and reduce the ion leakage. The proline, soluble sugar, and soluble protein contents significantly increased. By contrast, the electrolytic leakage and malondialdehyde accumulation in leaves significantly decreased. The shoot and root fresh and dry weights of the overexpression lines significantly increased. These results indicated that a significant correlation between CsPLDα overexpression and improved resistance to water deficit.
The plants with overexpressed CsPLDα exhibited lower water loss, higher leaf relative water content, and heavier fresh and dry matter accumulation than the WT. We proposed that CsPLDα was involved in the ABA-dependent pathway in mediating the stomatal closure and preventing the elevation of intracellular solute potential.
植物磷脂酶 D（PLD）可以水解膜磷脂产生第二信使分子磷酸脂酸（PA），它被认为在多种植物应激反应中发挥作用。PLD 和 PA 在植物生长、发育和细胞过程中都起着关键作用。PLD 被认为通过脱落酸（ABA）介导气孔运动的调节，以响应水分亏缺。在这项研究中，我们描述了黄瓜磷脂酶 Dα 基因（CsPLDα，GenBank 登录号 EF363796）在烟草（Nicotiana tabacum）对干旱胁迫的生长和耐受性中的作用。
烟草株系中 CsPLDα 的过表达与 ABA 的合成和代谢相关，调节干旱胁迫下快速的气孔关闭，减少水分流失。与处理前相比，转基因株系和野生型（WT）在干旱胁迫 16 天后 NtNCED1 的表达水平急剧上调，且转基因株系的表达水平明显高于 WT。与处理 0 天相比，8 天和 16 天后 NtAOG 的表达水平明显提高，且在转基因株系中明显低于 WT。ABA 含量在转基因株系中明显高于 WT。CsPLDα 的过表达可以增加渗透物含量，减少离子泄漏。脯氨酸、可溶性糖和可溶性蛋白含量显著增加。相比之下，叶片中的丙二醛积累和电解质渗漏显著减少。过表达系的地上部和根鲜重和干重显著增加。这些结果表明，CsPLDα 的过表达与提高对水分亏缺的抗性之间存在显著相关性。
过表达 CsPLDα 的植物比 WT 具有更低的水分损失、更高的叶片相对含水量以及更重的鲜重和干物质积累。我们提出，CsPLDα 参与了 ABA 依赖途径，介导气孔关闭和防止细胞内溶质势升高。
