Gardener BBM
Department of Botany and Plant Pathology, Michigan State University, East Lansing, Michigan 48824, USA.
Appl Environ Microbiol. 1998 Dec;64(12):4944-9. doi: 10.1128/AEM.64.12.4944-4949.1998.
Microbial rhizopine-catabolizing (Moc) activity was detected in serial dilutions of soil and rhizosphere washes. The activity observed generally ranged between 10(6) and 10(7) catabolic units per g, and the numbers of nonspecific culture-forming units were found to be approximately 10 times higher. A diverse set of 37 isolates was obtained by enrichment on scyllo-inosamine-containing media. However, none of the bacteria that were isolated were found to contain DNA sequences homologous to the known mocA, mocB, and mocC genes of Sinorhizobium meliloti L5-30. Twenty-one of the isolates could utilize an SI preparation as the sole carbon and nitrogen source for growth. Partial sequencing of 16S ribosomal DNAs (rDNAs) amplified from these strains indicated that five distinct bacterial genera (Arthrobacter, Sinorhizobium, Pseudomonas, Aeromonas, and Alcaligenes) were represented in this set. Only 6 of these 21 isolates could catabolize 3-O-methyl-scyllo-inosamine under standard assay conditions. Two of these, strains D1 and R3, were found to have 16S rDNA sequences very similar to those of Sinorhizobium meliloti. However, these strains are not symbiotically effective on Medicago sativa, and DNA sequences homologous to the nodB and nodC genes were not detected in strains D1 and R3 by Southern hybridization analysis.
在土壤和根际冲洗液的系列稀释液中检测到微生物根瘤菌素分解代谢（Moc）活性。观察到的活性通常在每克10(6)至10(7)个分解代谢单位之间，发现非特异性培养形成单位的数量大约高10倍。通过在含有棉子糖胺的培养基上富集获得了一组37个不同的分离株。然而，所分离的细菌中没有一个被发现含有与苜蓿中华根瘤菌L5-30已知的mocA、mocB和mocC基因同源的DNA序列。其中21个分离株可以利用一种SI制剂作为唯一的碳源和氮源进行生长。从这些菌株中扩增的16S核糖体DNA（rDNA）的部分测序表明，这一组中代表了五个不同的细菌属（节杆菌属、中华根瘤菌属、假单胞菌属、气单胞菌属和产碱菌属）。在标准测定条件下，这21个分离株中只有6个能够分解代谢3-O-甲基-棉子糖胺。其中两个菌株D1和R3，发现其16S rDNA序列与苜蓿中华根瘤菌的序列非常相似。然而，这些菌株对紫花苜蓿没有共生效果，通过Southern杂交分析在菌株D1和R3中未检测到与nodB和nodC基因同源的DNA序列。
