A calcium-dependent bacterial surface protein is involved in the attachment of rhizobia to peanut roots
A calcium-dependent bacterial surface protein is involved in the attachment of rhizobia to peanut roots
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DOI：
10.1139/w03-054
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发表时间：
2003-06-01
影响因子：
2.8
通讯作者：
Fabra, A
中科院分区：
文献类型：
--
作者：
Dardanelli, M;Angelini, J;Fabra, A
作为表征导致结核形成的裂缝进入感染过程中涉及的分子的项目的一部分，使用显微试验来可视化慢生根瘤菌sp.菌株SEMIA 6144和TAL 1000的细胞附着（通过引入表达绿色荧光蛋白GFP-S65T的质粒来标记）到花生上。定性和定量结果表明，附着强烈依赖于细菌的生长阶段。最佳的附着发生在细菌的后期或早期的固定阶段。慢生根瘤菌菌株的细胞表面蛋白在附着试验前提供抑制附着。在附着试验之前，用14kda的蛋白（从十二烷基硫酸钠中洗脱-细胞表面凝胶电泳）对根进行孵育，导致附着性强烈降低。粘附素似乎是一种钙结合蛋白，因为用EDTA处理的细胞被发现能够与粘附素处理的花生根部结合。由于这种蛋白质具有与报道的粘接素相同的特性，我们提出这种粘接素也参与根瘤菌与被裂缝进入过程感染的根豆科植物的附着过程。
As part of a project to characterize molecules involved in the crack-entry infection process leading to nodule development, a microscopic assay was used to visualize the attachment of cells of Bradyrhizobium sp. strains SEMIA 6144 and TAL 1000 (labelled by introducing a plasmid expressing constitutively the green fluorescent protein GFP-S65T) to Arachis hypogaea L. (peanut). Qualitative and quantitative results revealed that attachment was strongly dependent on the growth phase of the bacteria. Optimal attachment occurred when bacteria were at the late log or early stationary phase. Cell surface proteins from the Bradyrhizobium sp. strains inhibited the attachment when supplied prior to the attachment assay. Root incubation with a 14-kDa protein (eluted from sodium dodecyl sulphate - gel electrophoresis of the cell surface fraction) prior to the attachment assay resulted in a strong decrease of attachment. The adhesin appeared to be a calcium-binding protein, since cells treated with EDTA were found to be able to bind to adhesin-treated peanut roots. Since this protein has properties identical to those reported for rhicadhesin, we propose that this adhesin is also involved in the attachment process of rhizobia to root legumes that are infected by the crack-entry process.