Plant Gene Expression Center, USDA-ARS, Albany, California, USA.
Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA.
Annu Rev Phytopathol. 2022 Aug 26;60:77-96. doi: 10.1146/annurev-phyto-020620-100946. Epub 2022 Apr 6.
Although the phloem is a highly specialized tissue, certain pathogens, including phytoplasmas, spiroplasmas, and viruses, have evolved to access and live in this sequestered and protected environment, causing substantial economic harm. In particular, Liberibacter spp. are devastating citrus in many parts of the world. Given that most phloem pathogens are vectored, they are not exposed to applied chemicals and are therefore difficult to control. Furthermore, pathogens use the phloem network to escape mounted defenses. Our review summarizes the current knowledge of phloem anatomy, physiology, and biochemistry relevant to phloem/pathogen interactions. We focus on aspects of anatomy specific to pathogen movement, including sieve plate structure and phloem-specific proteins. Phloem sampling techniques are discussed. Finally, pathogens that cause particular harm to the phloem of crop species are considered in detail.
尽管韧皮部是一种高度特化的组织，但某些病原体，包括植原体、螺原体和病毒，已经进化到可以进入并生活在这个隔离和受保护的环境中，从而造成巨大的经济损失。特别是，韧皮部杆菌属 spp. 在世界许多地区对柑橘造成严重破坏。鉴于大多数韧皮部病原体都是通过媒介传播的，它们不会接触到施用的化学物质，因此很难控制。此外，病原体利用韧皮部网络来逃避已有的防御机制。我们的综述总结了与韧皮部/病原体相互作用相关的韧皮部解剖学、生理学和生物化学的现有知识。我们重点介绍了与病原体运动相关的解剖学方面，包括筛板结构和韧皮部特异性蛋白质。讨论了韧皮部取样技术。最后，详细考虑了对作物韧皮部造成特殊伤害的病原体。
