Nehela Yasser, Killiny Nabil
Department of Plant Pathology, Citrus Research and Education Center, University of Florida, 700 Experiment Station Rd., Lake Alfred, FL 33850, USA.
Department of Agricultural Botany, Faculty of Agriculture, Tanta University, Tanta 31511, Egypt.
Metabolites. 2020 Oct 13;10(10):409. doi: 10.3390/metabo10100409.
Huanglongbing (HLB), formerly known as citrus greening disease, is one of the most devastating bacterial diseases in citrus worldwide. HLB is caused by ' Liberibacter asiaticus' bacterium and transmitted by Both ' L. asiaticus' and its vector manipulate the host metabolism to fulfill their nutritional needs and/or to neutralize the host defense responses. Herein, we discuss the history of HLB and the complexity of its pathosystem as well as the geographical distribution of its pathogens and vectors. Recently, our recognition of physiological events associated with ' L. asiaticus' infection and/or -infestation has greatly improved. However, the roles of citrus metabolites in the development of HLB symptoms are still unclear. We believe that symptom development of HLB disease is a complicated process and relies on a multilayered metabolic network which is mainly regulated by phytohormones. Citrus metabolites play vital roles in the development of HLB symptoms through the modulation of carbohydrate metabolism, phytohormone homeostasis, antioxidant pathways, or via the interaction with other metabolic pathways, particularly involving amino acids, leaf pigments, and polyamines. Understanding how '. L. asiaticus' and its vector, , affect the metabolic pathways of their host is critical for developing novel, sustainable strategies for HLB management.
黄龙病（HLB），以前称为柑橘黄龙病，是全球柑橘中最具毁灭性的细菌性病害之一。HLB由亚洲韧皮杆菌引起，通过亚洲韧皮杆菌及其传播媒介传播。亚洲韧皮杆菌及其传播媒介都会操纵宿主的新陈代谢，以满足它们的营养需求和/或中和宿主的防御反应。在此，我们讨论了HLB的历史、其病理系统的复杂性以及其病原体和传播媒介的地理分布。最近，我们对与亚洲韧皮杆菌感染和/或侵染相关的生理事件的认识有了很大提高。然而，柑橘代谢物在HLB症状发展中的作用仍不清楚。我们认为，HLB病害的症状发展是一个复杂的过程，依赖于一个主要由植物激素调节的多层代谢网络。柑橘代谢物通过调节碳水化合物代谢、植物激素稳态、抗氧化途径，或通过与其他代谢途径相互作用，特别是涉及氨基酸、叶片色素和多胺的代谢途径，在HLB症状发展中发挥重要作用。了解亚洲韧皮杆菌及其传播媒介如何影响其宿主的代谢途径，对于制定新颖、可持续的HLB管理策略至关重要。
