Suppression of Arabidopsis vesicle-SNARE expression inhibited fusion of H2O2 containing vesicles with tonoplast and increased salt tolerance
Suppression of Arabidopsis vesicle-SNARE expression inhibited fusion of H2O2 containing vesicles with tonoplast and increased salt tolerance
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DOI：
10.1073/pnas.0604421103
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发表时间：
2006-11-21
影响因子：
11.1
通讯作者：
Levine, Alex
中科院分区：
文献类型：
--
作者：
Leshem, Yehoram;Melamed-Book, Naomi;Levine, Alex
胞内囊泡运输在真核细胞中执行基本功能，例如膜运输和将分子递送到其目的地。植物体内的一条主要的内吞途径是小泡向液泡的运输，这在植物的耐盐性中起着重要的作用。该途径中的最后一步由囊泡可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（v-SNARE）的AtVAMP 7 C家族介导，所述囊泡可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（v-SNARE）进行囊泡与液泡膜的融合。暴露于高盐条件会立即引起离子和渗透压，然后产生活性氧。在这里，我们表明，活性氧产生细胞内，在核内体的目标是中央液泡。反义AtVAMP 711基因或该家族的突变体抑制AtVAMP 7 C基因的表达抑制了含H2 O2的囊泡与液泡膜的融合，这导致形成保留在细胞质中的含H2 O2的巨囊泡。反义和突变体植物表现出改善的液泡功能，如维持Δ pH，减少从液泡释放钙，并大大提高植物耐盐性。反义植物表现出增加的钙依赖性蛋白激酶活性盐胁迫。在Delta Vamp 7敲除菌株中，在酵母系统中也观察到氧化应激期间液泡ATP酶活性的改善。有趣的是，AtVAMP 7 C基因的基于微阵列的分析显示，在盐胁迫期间野生型根中的大多数基因强烈下调，这表明液泡运输的进化分子适应。
Intracellular vesicle trafficking performs essential functions in eukaryotic cells, such as membrane trafficking and delivery of molecules to their destinations. A major endocytotic route in plants is vesicle trafficking to the vacuole that plays an important role in plant salt tolerance. The final step in this pathway is mediated by the AtVAMP7C family of vesicle soluble N-ethylmaleimide-sensitive factor attachment protein receptors (v-SNAREs) that carry out the vesicle fusion with the tonoplast. Exposure to high-salt conditions causes immediate ionic and osmotic stresses, followed by production of reactive oxygen species. Here, we show that the reactive oxygen species are produced intracellularly, in endosomes that were targeted to the central vacuole. Suppression of the AtVAMP7C genes expression by antisense AtVAMP711 gene or in mutants of this family inhibited fusion of H2O2-containing vesicles with the tonoplast, which resulted in formation of H2O2-containing megavesicles that remained in the cytoplasm. The antisense and mutant plants exhibited improved vacuolar functions, such as maintenance of Delta pH, reduced release of calcium from the vacuole, and greatly improved plant salt tolerance. The antisense plants exhibited increased calcium-dependent protein kinase activity upon salt stress. Improved vacuolar ATPase activity during oxidative stress also was observed in a yeast system, in a Delta Vamp7 knockout strain. Interestingly, a microarray-based analysis of the AtVAMP7C genes showed a strong down-regulation of most genes in wild-type roots during salt stress, suggesting an evolutionary molecular adaptation of the vacuolar trafficking.