Kuykendall L D, Weber D F
Appl Environ Microbiol. 1978 Dec;36(6):915-9. doi: 10.1128/aem.36.6.915-919.1978.
The fate of an inoculum strain of Rhizobium japonicum was studied using a genetically marked strain I-11O subline carrying resistance markers for azide, rifampin, and streptomycin (I-110 ARS). At the time of planting into a field populated with R. japonicum, seeds of soybean cultivars Kent and Peking were inoculated with varying cell densities of strain I-110 ARS. At various times during the growing season, surface-sterilized root nodules were examined for the presence of the inoculum strain by plating onto selective media. The recovery of the inoculum strain was unambiguous, varying, in the case of Kent cultivar, from about 5% with plants (sampled at 51 days) that had been inoculated with 3 X 10(8) cells per cm of row to about 20% with plants (sampled at 90 days) that had been inoculated with 3 X 10(9) cells per cm. The symbiotically incompatible interaction of Peking and strain 110 in Rhizobium-populated field soil was confirmed by the finding that at 60 days after planting, only one nodule in 360 sampled contained strain I-110 ARS. The use of genetically marked Rhizobium bacteria was found to provide for precise identification of the inoculum strain in nodules of field-grown soybeans.
使用携带叠氮化物、利福平及链霉素抗性标记的遗传标记菌株I-11O亚系,研究了日本根瘤菌接种菌株的命运(I-110 ARS)。在种植到已存在日本根瘤菌的田间时,用不同细胞密度的I-110 ARS菌株接种大豆品种Kent和Peking的种子。在生长季节的不同时间,通过接种到选择性培养基上,检查表面消毒的根瘤中接种菌株的存在情况。接种菌株的回收率是明确的,就Kent品种而言,接种每厘米行3×10⁸个细胞的植株(在51天取样)中约为5%,而接种每厘米行3×10⁹个细胞的植株(在90天取样)中约为20%。通过在种植60天后发现,在360个取样的根瘤中只有一个含有I-110 ARS菌株,证实了Peking与110菌株在已存在根瘤菌的田间土壤中的共生不亲和相互作用。发现使用遗传标记的根瘤菌可精确鉴定田间种植大豆根瘤中的接种菌株。