Abstract Plants have developed several strategies to overcome the broad scope of environmental challenges imposed by biotic and abiotic stresses, including chemical defenses known as secondary metabolites, natural products or, more recently, specialized metabolites, i.e. chemicals often not present in all plant species, which are mostly involved in ecochemical interactions. Nonprotein amino acids (NPAAs) comprise a large heterogeneous group of nitrogen-containing specialized metabolites with wide distribution in the Plant Kingdom, commonly found in several genera of Fabaceae. Various examples of toxic effects attributed to the NPAAs on animal, microbial and other plant cells are known and often related to their structural similarities to protein amino acids (PAAs). However, NPAAs have also been shown to play important roles in planta as protectant molecules against oxidative damage, besides increasing tolerance of different plant species to a variety of abiotic-induced stresses, such as drought, salinity, and temperature. In this review, we discuss well-established and novel functions recently unveiled for NPAAs, besides alternative modes of action proposed for these metabolites as key mediators and effectors in responses to abiotic stresses.

中文翻译：

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植物中的非生物胁迫和非蛋白质氨基酸

摘要 植物已经开发出多种策略来克服生物和非生物胁迫带来的广泛环境挑战，包括被称为次生代谢物、天然产物或最近的特殊代谢物的化学防御，即通常不存在于所有植物物种中的化学物质。主要参与生态化学相互作用。非蛋白氨基酸 (NPAAs) 包括一大类异质的含氮特殊代谢物，在植物界广泛分布，常见于豆科的几个属中。NPAA 对动物、微生物和其他植物细胞的毒性作用的各种例子是已知的，并且通常与它们与蛋白质氨基酸 (PAA) 的结构相似性有关。然而，除了增加不同植物物种对各种非生物诱导的胁迫（如干旱、盐度和温度）的耐受性之外，NPAA 还已被证明在植物中作为抗氧化损伤的保护分子发挥重要作用。在这篇综述中，我们讨论了最近为 NPAA 揭开的成熟和新颖的功能，除了为这些代谢物提出的替代作用模式之外，它们作为响应非生物胁迫的关键介质和效应物。