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维管束病害是发生在作物和多年生木本植物上最严重的植物病害类型之一。植物维管束病害通常由土传细菌、真菌和卵生菌侵染根木质部,在木质部中繁殖,阻碍水分和矿物质的运转,使叶片萎蔫和死亡,导致整株植物受损而最终死亡。对维管束病原物的生物学特性和植物抗病反应的分子机制进行深入了解并设计新的策略来控制维管束病害具有重要的理论和实际应用价值。本文系统地讨论了植物通过两类受体感知维管束病原菌、传递胞内信号、诱发寄主植物对维管束病菌的防卫反应。寄主植物对维管束病原菌物理防卫反应主要包括在木质部小室中形成甲基纤维素(tyloses)和维管束衣被(vascular coating)两个方面,从而阻止病原菌扩散。寄主植物对维管束病原菌的化学防卫反应主要是指木质部薄壁细胞的急剧代谢变化,导致木质部液体中不同蛋白质和次生代谢物的积累,从而杀死或抑制病原菌生长。化学防卫反应在木质部防卫反应中起主要作用。
Vascular disease is one of the most serious types of plant diseases that occur on crops and perennial woody plants. Plant vascular disease often infects root xylem by soil-borne bacteria, fungi, and oomycetes, propagates in the xylem, impedes the operation of moisture and minerals, leaves the leaf wilting and death, resulting in damage to the entire plant and eventual death. To understand the biological characteristics of vascular pathogens and the molecular mechanisms of plant disease resistance and to design new strategies to control vascular diseases have important theoretical and practical value. This article systematically discusses plants that sense vascular pathogen via two types of receptors, transmit intracellular signals, and induce host plant defense responses to vascular bundles. The host plant’s physical defense response to vascular pathogenic bacteria mainly consists of the formation of tyloses and vascular coatings in the xylem chambers, thereby preventing the spread of pathogens. The chemical defense response of the host plant to the vascular bundle pathogens mainly refers to the rapid metabolic changes of the xylem parenchyma cells, leading to the accumulation of different proteins and secondary metabolites in the xylem liquid, thus killing or inhibiting the growth of the pathogenic bacteria. Chemical defense reactions play a major role in the xylem defense response.