Alsubaie Qasi D, Al-Amri Abdullah A, Siddiqui Manzer H, Alamri Saud
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
Plant Physiol Biochem. 2024 Feb;207:108412. doi: 10.1016/j.plaphy.2024.108412. Epub 2024 Feb 1.
Arsenic (As) poses a significant environmental threat as a metalloid toxin, adversely affecting the health of both plants and animals. Strigolactones (SL) and nitric oxide (NO) are known to play crucial roles in plant physiology. Therefore, the present experiment was designed to investigate the potential cumulative role of SL (GR24-0.20 μM) and NO (100 μM) in mitigating the adverse effect of As (53 μM) by modulating physiological mechanisms in two genotypes of tomato (Riogrand and Super Strain 8). A sample randomized design with four replicates was used to arrange the experimental pots in the growth chamber. 45-d old both tomato cultivars under As toxicity exhibited reduced morphological attributes (root and shoot length, root and shoot fresh weight, and root and shoot dry weight) and physiological and biochemical characteristics [chlorophyll (Chl) a and b content, activity of δ-aminolevulinic acid dehydratase activity (an enzyme responsible for Chl biosynthesis), and carbonic anhydrase activity (an enzyme responsible for photosynthesis), and enhanced Chl degradation, overproduction of reactive oxygen species (ROS) and lipid peroxidation due to enhanced malondialdehyde (MDA) content. However, the combined application of SL and NO was more effective in enhancing the tolerance of both varieties to As toxicity compared to individual application. The combined application of SL and NO improved growth parameters, biosynthesis of Chls, NO and proline. However, the combined application significantly suppressed cellular damage by inhibiting MDA and overproduction of ROS in leaves and roots, as confirmed by the fluorescent microscopy study and markedly upregulated the antioxidant enzymes (catalase, peroxidase, superoxide dismutase, ascorbate dismutase and glutathione reductase) activity. This study provides clear evidence that the combined application of SL and NO supplementation significantly improves the resilience of tomato seedlings against As toxicity. The synergistic effect of SL and NO was confirmed by the application of cPTIO (an NO scavenger) with SL and NO. However, further molecular studies could be imperative to conclusively validate the simultaneous role of SL and NO in enhancing plant tolerance to abiotic stress.
砷（As）作为一种类金属毒素，对环境构成重大威胁，会对动植物健康产生不利影响。已知独脚金内酯（SL）和一氧化氮（NO）在植物生理过程中发挥关键作用。因此，本实验旨在研究SL（GR24 - 0.20 μM）和NO（100 μM）通过调节两种番茄基因型（里奥格兰德和超级8号）的生理机制，在减轻As（53 μM）的不利影响方面的潜在累积作用。采用具有四个重复的样本随机设计在生长室中布置实验盆。在As毒性条件下，45日龄的两个番茄品种均表现出形态学特征（根和茎长度、根和茎鲜重以及根和茎干重）以及生理生化特性[叶绿素（Chl）a和b含量、δ-氨基乙酰丙酸脱水酶活性（一种负责Chl生物合成的酶）和碳酸酐酶活性（一种负责光合作用的酶）降低，并且由于丙二醛（MDA）含量增加导致Chl降解增强、活性氧（ROS）过量产生和脂质过氧化。然而，与单独施用相比，SL和NO的联合施用在提高两个品种对As毒性的耐受性方面更有效。SL和NO的联合施用改善了生长参数、Chls、NO和脯氨酸的生物合成。然而，荧光显微镜研究证实，联合施用通过抑制叶片和根中的MDA和ROS过量产生，显著抑制了细胞损伤，并显著上调了抗氧化酶（过氧化氢酶、过氧化物酶、超氧化物歧化酶、抗坏血酸歧化酶和谷胱甘肽还原酶）的活性。本研究提供了明确的证据，表明SL和NO补充剂的联合施用显著提高了番茄幼苗对As毒性的恢复力。通过将cPTIO（一种NO清除剂）与SL和NO一起施用，证实了SL和NO的协同效应。然而，可能需要进一步的分子研究来最终验证SL和NO在增强植物对非生物胁迫耐受性方面的同时作用。
