A lipopolysaccharide mutant of Bradyrhizobium japonicum that uncouples plant from bacterial differentiation.
A lipopolysaccharide mutant of Bradyrhizobium japonicum that uncouples plant from bacterial differentiation.
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DOI：
10.1094/mpmi-4-332
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发表时间：
1991-07
期刊：
影响因子：
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通讯作者：
G. Stacey;J. So;L. Roth;B. Lakshmi SK;R. Carlson
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文献类型：
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作者：
G. Stacey;J. So;L. Roth;B. Lakshmi SK;R. Carlson
来自大豆慢生根瘤菌（Bradyrhizobium japonicum）不结瘤突变株ML142的含Tn5片段通过标记交换被引入大豆慢生根瘤菌61A101c菌株中，从而构建了JS314菌株。JS314菌株在对几种受试大豆品种进行接种时不能结瘤。然而，在少数几个品种上，有54%的接种植株诱导出了类似根瘤的结构。通过光学显微镜和电子显微镜对这些根瘤的超微结构进行了详细研究。这些根瘤内部没有细菌，具有中央维管组织（不同于正常根瘤的侧生维管组织），并且表皮细胞出现局部死亡。对JS314菌株细胞表面多糖的研究表明，该菌株的胞外多糖与野生型相同。然而，JS314菌株的脂多糖（LPS）与从野生型菌株中分离出的脂多糖有很大差异。具体来说，JS314菌株的LPS似乎缺少高分子量的LPS I形式，这强烈表明该LPS缺少O -链。糖基组成分析表明，突变株JS314的LPS缺少2,3 - 二 - O - 甲基鼠李糖、3 - O - 甲基鼠李糖、岩藻糖和奎诺糖胺。这些结果表明，大豆慢生根瘤菌中的LPS I对于细菌侵染大豆是必不可少的，但对于启动植物皮层细胞分裂（植物对侵染的早期反应）并不是必需的。
The Tn5-containing fragment from a non-nodulating mutant of Bradyrhizobium japonicum, strain ML142, was introduced into B. japonicum strain 61A101c by marker exchange to construct strain JS314. Strain JS314 failed to nodulate several soybean varieties tested. However, on a few varieties nodulelike structures were induced to a frequency of 54% of the plants inoculated. The ultrastructure of these nodules was studied in detail by light and electron microscopy. The nodules were devoid of internal bacteria, possessed central vascular tissue (unlike the lateral vascular tissue of a normal nodule), and exhibited localized cell death of epidermal cells. Study of the cell surface polysaccharides of strain JS314 revealed that the exopolysaccharide of this strain was identical to that of the wild type. However, the lipopolysaccharide (LPS) of strain JS314 showed gross differences from that isolated from the wild-type strain. Specifically, the LPS of strain JS314 appeared to lack the high molecular weight LPS I form, strongly suggesting that the LPS lacks the O-chain. Glycosyl-composition analysis showed that the LPS of mutant JS314 lacked 2,3-di-O-methylrhamnose, 3-O-methylrhamnose, fucose, and quinovosamine. These results indicate that LPS I in B. japonicum is essential for bacterial infection of soybean, but is not required to initiate plant cortical cell division, an early plant response to infection.