Multivesicular bodies participate in a cell wall-associated defence response in barley leaves attacked by the pathogenic powdery mildew fungus
Multivesicular bodies participate in a cell wall-associated defence response in barley leaves attacked by the pathogenic powdery mildew fungus
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DOI：
10.1111/j.1462-5822.2006.00683.x
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发表时间：
2006-06-01
影响因子：
3.4
通讯作者：
Van Bel, AJE
中科院分区：
文献类型：
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作者：
An, QL;Hückelhoven, R;Van Bel, AJE
局部的细胞壁修饰和抗菌化合物在真菌侵袭部位下的积累是植物抵抗真菌侵染的常见机制。在大麦叶片中，含有过氧化氢或酚类物质的光镜可见的囊泡状小体(VLB)经常聚集在细胞壁对位(syn.乳突)，其中生物营养白粉菌Blumeria graminis f.sp.Hordei(BGH)被叫停。通过超微结构分析，我们证明了BGH诱导的VLB呈现不同的结构。过氧化氢活性染料染色的VLB实际上是小乳突，而不是细胞质小泡。其他VLB为嗜欧体或多囊泡室、指定的附壁小体(PMB)和多囊泡小体(MVB)。MVB似乎遵循两条不同的途径：要么被液泡膜吞噬降解，要么与质膜融合，将其内部囊泡释放到附壁间隙，因此可能是PMBS的起源。MVB和PMB似乎是多组分试剂盒，可能含有积木，可以很容易地组装成乳头和抗菌化合物，以防止真菌渗透。最后，我们提出，释放的壁旁小泡可能类似于动物细胞中的外切体。
Localized cell wall modification and accumulation of antimicrobial compounds beneath sites of fungal attack are common mechanisms for plant resistance to fungal penetration. In barley (Hordeum vulgare) leaves, light-microscopically visible vesicle-like bodies (VLBs) containing H2O2 or phenolics frequently accumulate around cell wall appositions (syn. papillae), in which the penetration attempt of the biotrophic powdery mildew fungus Blumeria graminis f. sp. hordei (Bgh) is halted. By ultrastructural analyses, we demonstrated that the Bgh-induced VLBs represent different structures. VLBs intensively stained by H2O2-reactive dyes were actually small papillae instead of cytoplasmic vesicles. Other VLBs were identified as osmiophilic bodies or multivesicular compartments, designated paramural bodies (PMBs) and multivesicular bodies (MVBs). MVBs seemingly followed two distinct pathways: either they were engulfed by the tonoplast for degradation in the vacuole or they fused with the plasma membrane to release their internal vesicles into the paramural space and hence could be the origin of PMBs. MVBs and PMBs appeared to be multicomponent kits possibly containing building blocks to be readily assembled into papilla and antimicrobial compounds to be discharged against fungal penetration. Finally, we propose that released paramural vesicles might be similar to exosomes in animal cells.