Bargunam Soundaryaa, Roy Riyan, Shetty Devika, H Amisha S, V S Shukla, Babu Vidhu Sankar
Department of Plant Sciences, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India.
Department of Plant Sciences, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India.
Plant Physiol Biochem. 2025 Apr;221:109635. doi: 10.1016/j.plaphy.2025.109635. Epub 2025 Feb 10.
Melatonin, a versatile biomolecule, profoundly influences plant growth and resilience through its intricate regulation of metabolic pathways, circadian rhythms, and cellular processes. The current study elucidates melatonin's concentration-dependent biphasic effects on growth dynamics in Arabidopsis thaliana and Brassica nigra. While 50 μM melatonin optimized biomass accumulation and root elongation, higher concentrations (100 μM) elicited stress responses, underscoring its dual role as a growth promoter and stress modulator. Melatonin extended photosynthetic efficiency by modulating chlorophyll and carotenoid synthesis diurnally, offering protection against photodamage. Divergent responses between the two species, driven by species-specific metabolic reprogramming, were evident in pigment biosynthesis and antioxidant pathways. B. nigra displayed robust activation of flavonoid and phenylpropanoid pathways, cytokinin signaling, and enhanced oxidative defenses, contrasting with A. thaliana, where melatonin suppressed pigment precursors and antioxidant activation. Metabolomic analysis revealed melatonin's orchestration of hormonal crosstalk, involving auxins, gibberellins, and jasmonates, to fine-tune growth and stress adaptation. Stomatal dynamics and cell wall fortification in B. nigra highlighted melatonin's role in optimizing water-use efficiency and structural resilience under abiotic stress. Cytogenetic studies confirmed melatonin's role in safeguarding genomic integrity, regulating chromatin remodeling, and promoting DNA repair mechanisms, with B. nigra demonstrating adaptive genomic strategies under stress. Moreover, melatonin influenced critical metabolic pathways, including polyamine biosynthesis, sulfur metabolism, and nucleotide regulation, emphasizing its multifaceted impact on cellular homeostasis. These findings position melatonin as a cornerstone molecule in plant biotechnology, with potential applications in enhancing crop resilience and productivity under fluctuating environmental conditions.
褪黑素是一种多功能生物分子，通过对代谢途径、昼夜节律和细胞过程的复杂调控，深刻影响植物的生长和抗逆性。当前的研究阐明了褪黑素对拟南芥和黑芥生长动态的浓度依赖性双相效应。虽然50 μM的褪黑素可优化生物量积累和根伸长，但较高浓度（100 μM）会引发应激反应，突显了其作为生长促进剂和应激调节剂的双重作用。褪黑素通过昼夜调节叶绿素和类胡萝卜素的合成来提高光合效率，提供对光损伤的保护。在色素生物合成和抗氧化途径中，由物种特异性代谢重编程驱动的两个物种之间的不同反应很明显。黑芥显示出类黄酮和苯丙烷途径、细胞分裂素信号传导的强烈激活以及氧化防御增强，这与拟南芥形成对比，在拟南芥中褪黑素抑制色素前体和抗氧化激活。代谢组学分析揭示了褪黑素对激素串扰的调控，涉及生长素、赤霉素和茉莉酸，以微调生长和应激适应。黑芥的气孔动态和细胞壁强化突出了褪黑素在非生物胁迫下优化水分利用效率和结构抗逆性方面的作用。细胞遗传学研究证实了褪黑素在保护基因组完整性、调节染色质重塑和促进DNA修复机制方面的作用，黑芥在胁迫下展示了适应性基因组策略。此外，褪黑素影响关键代谢途径，包括多胺生物合成、硫代谢和核苷酸调节，强调了其对细胞稳态的多方面影响。这些发现将褪黑素定位为植物生物技术中的基石分子，在波动环境条件下提高作物抗逆性和生产力方面具有潜在应用。
