Abstract Environmental stress and pathogen infection are the major limiting factors in worldwide horticulture production, resulting in huge yield loss. Melatonin (N-acetyl-5-methoxytryptamine) has gained a great interest in plant science research owing to its multifaceted role in plant systems. Melatonin mediated efficient reactive oxygen species scavenging and activation of antioxidant defence responses is the two major mechanisms to cope with most of the abiotic stresses and pathogen infections. Besides that, the activation of gene expression of stress-specific genes, antioxidant enzyme genes and pathogenesis-related genes make it a master regulator in plant defence responses under pathogen infection and environmental stresses. Additionally, hormonal cross-talk of melatonin with other phytohormones in regulating drought stress and virus infection gives an idea to explore the possibilities of such a mechanism in other stresses in diverse horticultural crops. The complementary effect of melatonin with fungicides is giving new hope in reducing the burden of exhaustive use of toxic chemicals in vegetables and fruit crops. Melatonin can play an essential role in combating sequential and simultaneous combined stresses in crop plants which are an emerging challenge these days. Our review highlighted the functions of melatonin in ameliorating major abiotic (heat, cold, drought, and salt) and biotic (fungi, virus, bacteria, and insects) stresses of horticultural crops and elucidated the resulting physiological and molecular mechanism. The versatile role of this biological molecule in anti-stress regulation showing successful cases of growth promotion and enhanced resistance makes it suitable for environment-friendly horticultural crop production and to ensure food safety.

中文翻译：

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褪黑激素在减轻园艺作物的非生物和生物胁迫中的新作用

摘要 环境胁迫和病原体感染是世界范围内园艺生产的主要限制因素，造成了巨大的产量损失。褪黑激素（N-乙酰基-5-甲氧基色胺）因其在植物系统中的多方面作用而引起了植物科学研究的极大兴趣。褪黑激素介导的有效活性氧清除和抗氧化防御反应的激活是应对大多数非生物胁迫和病原体感染的两种主要机制。除此之外，胁迫特异性基因、抗氧化酶基因和发病相关基因的基因表达的激活使其成为病原体感染和环境胁迫下植物防御反应的主要调节因子。此外，褪黑激素与其他植物激素在调节干旱胁迫和病毒感染方面的激素串扰为探索这种机制在不同园艺作物的其他胁迫中的可能性提供了思路。褪黑激素与杀菌剂的互补作用为减轻蔬菜和水果作物中有毒化学品的过度使用带来的负担带来了新的希望。褪黑激素可以在对抗作物植物中的连续和同时组合压力方面发挥重要作用，这是当今新出现的挑战。我们的综述强调了褪黑激素在改善园艺作物的主要非生物（热、冷、干旱和盐）和生物（真菌、病毒、细菌和昆虫）胁迫方面的作用，并阐明了由此产生的生理和分子机制。