Yang Huaiyu, Ludewig Uwe
a Institute of Crop Science; Nutritional Crop Physiology; University of Hohenheim; Stuttgart, Germany.
Plant Signal Behav. 2014;9(7):e28933. doi: 10.4161/psb.28933.
Lysine is an essential amino acid for human nutrition, which is generally low in cereal diets. Its biosynthesis via the aspartate-pathway and catabolism is controlled by complex feedback mechanisms. Recently, aspartate-derived amino acids were found to be elevated during pathogen infection in Arabidopsis and a lysine catabolite, pipecolic acid, was identified as critical regulator of systemic acquired resistance. Pipecolic acid is mobile in plants, functions as an intensifier of defense responses and mediates systemic acquired resistance establishment via signal amplification. The altered pathogen defense in several mutants with altered homeostasis of aspartate-derived amino acids, such as lysine, had already provided a genetic link with amino acid homeostasis. Furthermore, the modification of amino acid transport and distribution within tissues not only affected the plant growth performance, but also the plant-pathogen interaction. The ectopic overexpression of a gene encoding a high affinity importer with preference to basic amino acids, such as lysine, cationic amino acid transporter1 (CAT1), improved the disease resistance to a hemibiotrophic bacterial pathogen in Arabidopsis via a constitutively activated salicylic acid pathway. The importance of Asp-derived amino acid homeostasis for plant systemic acquired resistance and on overall plant growth performance may be relevant to resistance and nutritional quality breeding. Whether nitrogen fertilization has an impact on crop pest control management via amino acid homeostasis is briefly discussed.
赖氨酸是人类营养中的一种必需氨基酸，在谷类食物中含量通常较低。其通过天冬氨酸途径的生物合成及分解代谢受复杂的反馈机制控制。最近发现，在拟南芥受病原体感染期间，源自天冬氨酸的氨基酸水平会升高，并且一种赖氨酸分解代谢物——哌啶酸被确定为系统获得性抗性的关键调节因子。哌啶酸在植物中具有移动性，作为防御反应的增强剂，并通过信号放大介导系统获得性抗性的建立。在一些源自天冬氨酸的氨基酸（如赖氨酸）稳态发生改变的突变体中，病原体防御的改变已经提供了与氨基酸稳态的遗传联系。此外，氨基酸在组织内的运输和分布的改变不仅影响植物的生长性能，还影响植物与病原体的相互作用。异位过表达一个编码对碱性氨基酸（如赖氨酸）具有偏好的高亲和力转运体的基因，即阳离子氨基酸转运体1（CAT1），通过组成型激活的水杨酸途径提高了拟南芥对一种半活体营养型细菌病原体的抗病性。源自天冬氨酸的氨基酸稳态对植物系统获得性抗性和整体植物生长性能的重要性可能与抗性和营养品质育种相关。本文简要讨论了氮肥是否通过氨基酸稳态对作物病虫害防治管理产生影响。
