A Rhizobium leguminosarum lipopolysaccharide lipid-A mutant induces nitrogen-fixing nodules with delayed and defective bacteroid formation
A Rhizobium leguminosarum lipopolysaccharide lipid-A mutant induces nitrogen-fixing nodules with delayed and defective bacteroid formation
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DOI：
10.1094/mpmi.2004.17.3.283
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发表时间：
2004-03-01
影响因子：
3.5
通讯作者：
Sherrier, DJ
中科院分区：
文献类型：
--
作者：
Vedam, V;Haynes, JG;Sherrier, DJ
豌豆根瘤菌的脂多糖。蚕豆3841与根瘤菌科的所有其它成员一样，可能除了茎瘤固氮根瘤菌（Azorhizobiumcaulinodans）之外，在其脂质A区含有非常长链的脂肪酸; 27-羟基二十八烷酸（27 OHC 28：0）。然而，这种残留物的确切功能和重要性尚不清楚。在这项工作中，以前构建的突变体，根瘤菌豆类bv。分析了脂肪酸残基缺乏的蚕豆22的共生表型。虽然该突变体能够形成固氮结节，但使用光学和电子显微镜对结瘤的时间和效率进行的详细研究表明，结瘤和结节组织侵入的发生有延迟。此外，显微镜检查显示，突变体不能正常分化形成许多形状不规则的类菌体，所得到的成熟类菌体异常大，并且几个类菌体经常被封闭在一个共生体膜中，这是亲本类菌体没有观察到的特征。此外，突变根瘤固氮酶生产的发病延迟，并表现出减少固氮酶。测试期。这些结果表明，缺乏27 OHC 28：0的脂质A突变体类细菌的结果在改变膜的性质，是必不可少的正常类细菌的发展。
Lipopolysaccharides from pea-nodulating strain Rhizobium leguminosarum bv. viciae 3841, as all other members of the family Rhizobiaceae with the possible exception of Azorhizobium caulinodans, contains a very long chain fatty acid; 27-hydroxyoctacosanoic acid (27OHC28:0) in its lipid A region. The exact function and importance of this residue, however, is not known. In this work, a previously constructed mutant, Rhizobium leguminosarum bv. viciae 22, deficient in the fatty acid residue, was analyzed for its symbiotic phenotype. While the mutant was able to form nitrogen-fixing nodules, a detailed study of the timing and efficiency of nodulation using light and electron microscopy showed that there was a delay in the onset of nodulation and nodule tissue invasion. Further, microscopy showed that the mutant was unable to differentiate normally forming numerous irregularly shaped bacteroids, that the resultant mature bacteroids were unusually large, and that several bacteroids were frequently enclosed in a single symbiosome membrane, a feature not observed with parent bacteroids. In addition, the mutant nodules were delayed in the onset of nitrogenase production and showed reduced nitrogenase throughout. the testing period. These results imply that the lack of 27OHC28:0 in the lipid A in mutant bacteroids results in altered membrane properties that are essential for the development of normal bacteroids.