Department of Ornamental Plants and Agricultural Biotechnology, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel.
Biotechnol Adv. 2023 Nov;68:108246. doi: 10.1016/j.biotechadv.2023.108246. Epub 2023 Aug 29.
Phenylalanine has a unique role in plants as a source of a wide range of specialized metabolites, named phenylpropanoids that contribute to the adjustment of plants to changing developmental and environmental conditions. The profile of these metabolites differs between plants and plant organs. Some of the prominent phenylpropanoids include anthocyanins, phenolic acids, flavonoids, tannins, stilbenes, lignins, glucosinolates and benzenoid phenylpropanoid volatiles. Phenylalanine biosynthesis, leading to increased phenylpropanoid levels, is induced under stress. However, high availability of phenylalanine in plants under non-stressed conditions can be achieved either by genetically engineering plants to overproduce phenylalanine, or by external treatment of whole plants or detached plant organs with phenylalanine solutions. The objective of this review is to portray the many effects that increased phenylalanine availability has in plants under non-stressed conditions, focusing mainly on external applications. These applications include spraying and drenching whole plants with phenylalanine solutions, postharvest treatments by dipping fruit and cut flower stems, and addition of phenylalanine to cell suspensions. The results of these treatments include increased fragrance in flowers, increased aroma and pigmentation in fruit, increased production of health promoting metabolites in plant cell cultures, and increased resistance of plants, pre- and post-harvest, to a wide variety of pathogens. These effects suggest that plants can very efficiently uptake phenylalanine from their roots, leaves, flowers and fruits, translocate it from one organ to the other and between cell compartments, and metabolize it into phenylpropanoids. The mechanisms by which Phe treatment increases plant resistance to pathogens reveal new roles of phenylpropanoids in induction of genes related to the plant immune system. The simplicity of treatments with phenylalanine open many possibilities for industrial use. Many of the phenylalanine-treatment effects on increased resistance to plant pathogens have also been successful in commercial field trials.
苯丙氨酸在植物中具有独特的作用，是多种特殊代谢物（称为苯丙烷类化合物）的来源，有助于植物适应不断变化的发育和环境条件。这些代谢物的特征在不同的植物和植物器官之间有所不同。一些突出的苯丙烷类化合物包括花青素、酚酸、类黄酮、单宁、芪类、木质素、芥子油苷和苯丙素挥发性化合物。在胁迫下，苯丙氨酸生物合成增加，导致苯丙烷类化合物水平升高。然而，在非胁迫条件下，植物中苯丙氨酸的高可用性可以通过基因工程使植物过量产生苯丙氨酸来实现，或者通过用苯丙氨酸溶液处理整株植物或离体植物器官来实现。本综述的目的是描绘在非胁迫条件下增加苯丙氨酸可用性对植物的许多影响，主要侧重于外部应用。这些应用包括用苯丙氨酸溶液喷洒和浇灌整株植物、用果实和切花茎浸渍进行采后处理，以及向细胞悬浮液中添加苯丙氨酸。这些处理的结果包括增加花的香味、增加果实的香气和色泽、增加植物细胞培养物中促进健康的代谢物的产生，以及增加植物在采前和采后的抗多种病原体的能力。这些效应表明，植物可以从根部、叶片、花朵和果实中非常有效地吸收苯丙氨酸，将其从一个器官转运到另一个器官，并在细胞隔室之间进行代谢，形成苯丙烷类化合物。苯丙氨酸处理增加植物对病原体抗性的机制揭示了苯丙烷类化合物在诱导与植物免疫系统相关的基因方面的新作用。苯丙氨酸处理的简单性为工业用途开辟了许多可能性。许多用苯丙氨酸处理增加植物对病原体抗性的效应在商业田间试验中也取得了成功。
