Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv, 69978, Israel.
Protoplasma. 2011 Jan;248(1):117-30. doi: 10.1007/s00709-010-0247-0. Epub 2010 Nov 30.
The turnover of callose (β-1,3-glucan) within cell walls is an essential process affecting many developmental, physiological and stress related processes in plants. The deposition and degradation of callose at the neck region of plasmodesmata (Pd) is one of the cellular control mechanisms regulating Pd permeability during both abiotic and biotic stresses. Callose accumulation at Pd is controlled by callose synthases (CalS; EC 2.4.1.34), endogenous enzymes mediating callose synthesis, and by β-1,3-glucanases (BG; EC 3.2.1.39), hydrolytic enzymes which specifically degrade callose. Transcriptional and posttranslational regulation of some CalSs and BGs are strongly controlled by stress signaling, such as that resulting from pathogen invasion. We review the role of Pd-associated callose in the regulation of intercellular communication during developmental, physiological, and stress response processes. Special emphasis is placed on the involvement of Pd-callose in viral pathogenicity. Callose accumulation at Pd restricts virus movement in both compatible and incompatible interactions, while its degradation promotes pathogen spread. Hence, studies on mechanisms of callose turnover at Pd during viral cell-to-cell spread are of importance for our understanding of host mechanisms exploited by viruses in order to successfully spread within the infected plant.
壁中胼胝质（β-1,3-葡聚糖）的周转率是影响植物许多发育、生理和应激相关过程的重要过程。质膜通道（Pd）颈部区胼胝质的沉积和降解是调节 Pd 通透性的细胞控制机制之一，在非生物和生物胁迫下都起作用。Pd 处的胼胝质积累受胼胝质合成酶（CalS；EC 2.4.1.34）、内源性酶介导的胼胝质合成酶和 β-1,3-葡聚糖酶（BG；EC 3.2.1.39）控制，这些酶特异性降解胼胝质。一些 CalS 和 BG 的转录和翻译后调控受胁迫信号强烈控制，如病原体入侵引起的信号。我们综述了 Pd 相关胼胝质在发育、生理和应激反应过程中调节细胞间通讯的作用。特别强调了 Pd-胼胝质在病毒致病性中的作用。Pd 处胼胝质的积累限制了病毒在亲和和非亲和互作中的运动，而其降解则促进了病原体的传播。因此，研究病毒在细胞间传播过程中 Pd 处胼胝质周转率的机制对于我们理解病毒利用宿主机制在受感染植物内成功传播非常重要。
