Jiang Dexing, Ou Ying, Jiang Gongcheng, Dai Gu, Liu Shaohua, Chen Guoxiang
Jiangsu Key Laboratory of Innovative Applications of Bioresources and Functional Molecules, College of Life Sciences and Chemical Engineering, Jiangsu Second Normal University, Nanjing, 211222, China.
Jiangsu Key Laboratory of Innovative Applications of Bioresources and Functional Molecules, College of Life Sciences and Chemical Engineering, Jiangsu Second Normal University, Nanjing, 211222, China.
Plant Physiol Biochem. 2025 Feb;219:109433. doi: 10.1016/j.plaphy.2024.109433. Epub 2024 Dec 19.
Seed priming can effectively enhance the plant's ability to withstand stress during subsequent growth and development; however, the role of melatonin-priming in attenuating aluminum (Al) toxicity remain unknown. In this study, 10, 50 and 100 μM melatonin were selected for rice seed priming to investigate the protective effects and potential mechanisms of melatonin against Al toxicity. Al stress inhibited seed germination by induction of abscisic acid (ABA) accumulation and reduction of α-amylase activity. However, melatonin-priming substantially rescued the Al-induced poor germination of seeds, as evidenced by less ABA content and higher α-amylase activity. Compared to no priming under Al stress, melatonin-priming significantly increased root elongation and plant fresh weight of rice seedlings by 135.1% and 39.4%, respectively. Melatonin-priming scavenged Al-induced superoxide anion (O·) and hydrogen peroxide (HO) bursts by activating the antioxidant enzymes (superoxide dismutase and catalase) and antioxidants (ascorbate and glutathione) in root tips, thereby reducing malondialdehyde (MDA) and callose levels and ultimately mitigating oxidative damage. Furthermore, melatonin-priming enhanced Al resistance by inhibiting Al uptake into the symplast through increased citric acid secretion. The decrease of Al deposition in the cell wall was attributed to melatonin-stimulated reduction of cell wall pectin and hemicellulose contents under Al stress. Collectively, these findings reveal a positive role of melatonin-priming in alleviating Al toxicity in plants.
种子引发可以有效增强植物在后续生长发育过程中抵御胁迫的能力；然而，褪黑素引发在减轻铝（Al）毒性方面的作用仍不清楚。在本研究中，选择10、50和100 μM的褪黑素对水稻种子进行引发处理，以研究褪黑素对铝毒性的保护作用及潜在机制。铝胁迫通过诱导脱落酸（ABA）积累和降低α-淀粉酶活性来抑制种子萌发。然而，褪黑素引发显著挽救了铝诱导的种子萌发不良，表现为ABA含量降低和α-淀粉酶活性升高。与铝胁迫下未引发处理相比，褪黑素引发使水稻幼苗的根伸长和植株鲜重分别显著增加了135.1%和39.4%。褪黑素引发通过激活根尖中的抗氧化酶（超氧化物歧化酶和过氧化氢酶）和抗氧化剂（抗坏血酸和谷胱甘肽）来清除铝诱导的超氧阴离子（O·）和过氧化氢（H₂O₂）爆发，从而降低丙二醛（MDA）和胼胝质水平，最终减轻氧化损伤。此外，褪黑素引发通过增加柠檬酸分泌来抑制铝向共质体的吸收，从而增强对铝的抗性。细胞壁中铝沉积的减少归因于褪黑素在铝胁迫下刺激细胞壁果胶和半纤维素含量的降低。总的来说，这些发现揭示了褪黑素引发在减轻植物铝毒性方面的积极作用。
