RHIZOBIUM-LEGUMINOSARUM CFN42 GENETIC REGIONS ENCODING LIPOPOLYSACCHARIDE STRUCTURES ESSENTIAL FOR COMPLETE NODULE DEVELOPMENT ON BEAN-PLANTS
RHIZOBIUM-LEGUMINOSARUM CFN42 GENETIC REGIONS ENCODING LIPOPOLYSACCHARIDE STRUCTURES ESSENTIAL FOR COMPLETE NODULE DEVELOPMENT ON BEAN-PLANTS
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DOI：
10.1128/jb.171.1.8-15.1989
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发表时间：
1989-01-01
影响因子：
3.2
通讯作者：
NOEL, KD
中科院分区：
文献类型：
--
作者：
CAVA, JR;ELIAS, PM;NOEL, KD
从豆类根瘤菌CFN42中分离到8株脂多糖合成缺陷的共生突变体。这8个菌株在接种到豆类植物上时，产生了缺乏受感染细胞的白色小结节。突变株中未检测到或极大地减少了完整的内毒素(LPSI)的含量，而缺失O抗原的内毒素(LPSII)的数量则大大增加。在部分突变体的提取液中检测到明显的在十二烷基硫酸钠-聚丙烯酰胺凝胶上的内毒素在内毒素I和内毒素II之间迁移的条带。突变菌株通过野生型基因组粘粒文库中的DNA补充野生型内毒素I含量和抗原性。大多数突变集中在两个基因区域；一个突变位于第三个区域。在来自其中两个地区的DNA的补充下，菌株产生了健康的固氮根瘤。由另一个基因区域补充野生型内毒素含量的菌株诱导的根瘤显示很少或没有固氮酶活性，尽管这种DNA的存在明显促进了根瘤的发育。这些结果支持这样一种观点，即正常数量的完整的内毒素结构是豆类植物侵染线索发育所必需的。
Eight symbiotic mutants defective in lipopolysaccharide (LPS) synthesis were isolated from Rhizobium leguminosarum biovar phaseoli CFN42. These eight strains elicited small white nodules lacking infected cells when inoculated onto bean plants. The mutants had undetectable or greatly diminished amounts of the complete LPS (LPS I), whereas amounts of an LPS lacking the O antigen (LPS II) greatly increased. Apparent LPS bands that migrated between LPS I and LPS II on sodium dodecyl sulfate-polyacrylamide gels were detected in extracts of some of the mutants. The mutant strains were complemented to wild-type LPS I content and antigenicity by DNA from a cosmid library of the wild-type genome. Most of the mutations were clustered in two genetic regions; one mutation was located in a third region. Strains complemented by DNA from two of these regions produced healthy nitrogen-fixing nodules. Strains complemented to wild-type LPS content by the other genetic region induced nodules that exhibited little or no nitrogenase activity,although nodule development was obviously enhanced by the presence of this DNA. The results support the idea that complete LPS structures, in normal amounts, are necessary for infection thread development in bean plants.