Laboratory of Plant Biotechnology, Faculty of Sciences of Sfax, University of Sfax, Route Soukra, BP 1171, 3000, Sfax, Tunisia.
Laboratory of Toxicology-Microbiology and Environmental Health (17ES06), Faculty of Sciences of Sfax, University of Sfax, BP1171, 3000, Sfax, Tunisia.
Biotechnol Lett. 2022 Nov;44(11):1323-1336. doi: 10.1007/s10529-022-03299-y. Epub 2022 Sep 13.
The present study aimed to explore the eliciting effects of increasing concentrations (50, 100, and 200 µM) of methyl jasmonate (MeJA). We cultivated actively proliferating buds of Phoenix dactylifera L. cv. Barhee in a temporary immersion system and we monitored the bioactive compound accumulation after 7 days of culture.
Total phenolic (TPC) and flavonoid (TFC) contents were determined by high-performance liquid chromatography (HPLC), Fourier-transform infrared (FTIR), and radical scavenging activity using DPPH and ABTS assays. We also explored the activity of phenylpropanoid pathway enzymes, namely phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL) and polyphenol oxidase (PPO).
Our results revealed that MeJA treatment induced oxidative stress, and at the same time increased the activity of related defense enzymes in a dose-dependent manner. Exogenous application of MeJA at 200 µM increased ROS (two fold), hydrogen peroxide (3.7 fold), nitric oxide (14 fold), MDA (6.3 fold), superoxide dismutase (5.9 fold), catalase (4.4 fold) and guaiacol peroxidase (3.87 fold). Furthermore, the results demonstrated that 200 µM MeJA treatment enhanced the activities of PAL (3.65 fold), TAL (4.35 fold), PPO (threefold) and increased TPC (twofold) and TFC (1.75 fold) contents in buds cultures higher than the control. HPLC analysis showed that buds cultures exposed to 200 µM MeJA accumulated maximum amount of catechin (11 fold), 4-hydroxybenzoic acid (1.48 fold), caffeic acid (2.5 fold) and p-coumaric acid (1.76 fold) and demonstrate antioxidant capacity with the lowest DPPH (114.5 µg ml) and ABTS (90.2 µg ml) IC50 values on day 7 of culture as compared to the control. The MeJA in the culture medium directly reduced cell viability in a dose dependent manner up to 35% with the highest concentration.
The results of this study has revealed, for the first time, that MeJA offers a promising potential for the production of phenolic compound in Phoenix dactylifera L. buds.
本研究旨在探讨茉莉酸甲酯（MeJA）浓度递增（50、100 和 200µM）对其的诱导作用。我们在暂态浸没法中培养活跃增殖的凤凰木（Phoenix dactylifera L. cv. Barhee）芽，并在培养 7 天后监测生物活性化合物的积累情况。
采用高效液相色谱法（HPLC）、傅里叶变换红外光谱（FTIR）和 DPPH 和 ABTS 测定法测定总酚（TPC）和类黄酮（TFC）含量。我们还探索了苯丙氨酸解氨酶（PAL）、酪氨酸解氨酶（TAL）和多酚氧化酶（PPO）等苯丙烷途径酶的活性。
结果表明，MeJA 处理诱导了氧化应激，同时以剂量依赖的方式增加了相关防御酶的活性。200µM 的 MeJA 外源处理使 ROS（增加两倍）、过氧化氢（增加 3.7 倍）、一氧化氮（增加 14 倍）、MDA（增加 6.3 倍）、超氧化物歧化酶（增加 5.9 倍）、过氧化氢酶（增加 4.4 倍）和愈创木酚过氧化物酶（增加 3.87 倍）。此外，结果表明，200µM MeJA 处理使 PAL（增加 3.65 倍）、TAL（增加 4.35 倍）、PPO（增加三倍）的活性增强，并使芽培养物中的 TPC（增加两倍）和 TFC（增加 1.75 倍）含量高于对照。HPLC 分析表明，与对照相比，暴露于 200µM MeJA 的芽培养物积累了最大量的儿茶素（增加 11 倍）、4-羟基苯甲酸（增加 1.48 倍）、咖啡酸（增加 2.5 倍）和对香豆酸（增加 1.76 倍），并表现出最低的 DPPH（114.5µgml）和 ABTS（90.2µgml）IC50 值，具有抗氧化能力，培养第 7 天。MeJA 在培养基中以剂量依赖的方式直接降低细胞活力，最高浓度可达 35%。
本研究首次表明，MeJA 为凤凰木芽中酚类化合物的生产提供了有前景的潜力。
