高pH水平的碱性胁迫可以显着影响植物的生长和存活。酶9-顺式环氧类胡萝卜素双加氧酶(NCED)是脱落酸(ABA)生物合成的关键瓶颈,使其对调节应力耐受性至关重要。这里,我们表明,过表达OsNCED3的水稻品系使ABA含量增加了高达50.90%,并改善了许多参与胁迫反应的基因的转录水平,从而显着提高了幼苗的存活率。OsNCED3的过表达增加了总叶绿素的干重含量,脯氨酸,可溶性糖,淀粉,和水稻幼苗抗氧化酶的活性,在降低O2含量的同时,在10、15和20mmolL-1Na2CO3模拟的水培碱性胁迫条件下,H2O2和丙二醛。此外,过表达OsNCED3的水稻系OsNCED3的表达显着增加;ABA反应相关基因OsSalT和OsWsi18;离子稳态相关基因OsAKT1,OsHKT1;5,OsSOS1和OsNHX5;和ROS清除相关基因OsCu/Zn-SOD,OsFe-SOD,OsPOX1,OsCATA,OsCATB,水稻幼苗叶片中的OsAPX1。这些发现的结果表明,OsNCED3的过表达上调了内源ABA水平和应激反应基因的表达,这代表了一种提高水稻幼苗耐碱性的创新分子方法。
Alkaline stress with high pH levels could significantly influence plant growth and survival. The enzyme 9-cis-epoxycarotenoid dioxygenase (NCED) serves as a critical bottleneck in the biosynthesis of abscisic acid (ABA), making it essential for regulating stress tolerance. Here, we show that OsNCED3-overexpressing rice lines have increased ABA content by up to 50.90% and improved transcription levels of numerous genes involved in stress responses that significantly enhance seedling survival rates. Overexpression of OsNCED3 increased the dry weight contents of the total chlorophyll, proline, soluble sugar, starch, and the activities of antioxidant enzymes of rice seedlings, while reducing the contents of O2·-, H2O2, and malondialdehyde under hydroponic alkaline stress conditions simulated by 10, 15, and 20 mmol L-1 of Na2CO3. Additionally, the OsNCED3-overexpressing rice lines exhibited a notable increase in the expression of OsNCED3; ABA response-related genes OsSalT and OsWsi18; ion homeostasis-related genes OsAKT1, OsHKT1;5, OsSOS1, and OsNHX5; and ROS scavenging-related genes OsCu/Zn-SOD, OsFe-SOD, OsPOX1, OsCATA, OsCATB, and OsAPX1 in rice seedling leaves. The results of these findings suggest that overexpression of OsNCED3 upregulates endogenous ABA levels and the expression of stress response genes, which represents an innovative molecular approach for enhancing the alkaline tolerance of rice seedlings.