Agrigenetics Advanced Science Company, Madison, Wisconsin 53716.
Appl Environ Microbiol. 1990 May;56(5):1333-41. doi: 10.1128/aem.56.5.1333-1341.1990.
A broad-host-range plasmid, pEA2-21, containing a Bradyrhizobium japonicum nodABC'-'lacZ translational fusion was used to identify strain-specific inhibitors of the genes required for soybean nodulation, the common nod genes. The responses of type strains of B. japonicum serogroups USDA 110, USDA 123, USDA 127, USDA 129, USDA 122, and USDA 138 to nod gene inhibitors were compared. Few compounds inhibited nod gene expression in B. japonicum USDA 110. In contrast, nod gene expression in strains belonging to several other serogroups was inhibited by most of the flavonoids tested. However, the application of two of these strain-specific compounds, chrysin and naringenin, had little effect on the pattern of competition between indigenous and inoculum strains of B. japonicum in greenhouse and field trials. Preliminary studies with radiolabeled chrysin and naringenin suggest that the different responses to nod gene inhibitors may be partly due to the degree to which plant flavonoids can be metabolized by each strain.
一个广泛宿主范围的质粒,pEA2-21,包含了一个日本根瘤菌 nodABC'-'lacZ 翻译融合,被用来鉴定大豆结瘤所必需的基因的菌株特异性抑制剂,即常见的结瘤基因。比较了美国农业部 110、123、127、129、122 和 138 血清型的日本根瘤菌的类型菌株对结瘤基因抑制剂的反应。少数化合物抑制了美国农业部 110 日本根瘤菌中的结瘤基因表达。相比之下,属于其他几个血清型的菌株的结瘤基因表达被大多数测试的类黄酮所抑制。然而,应用两种菌株特异性化合物,白杨素和柚皮素,对温室和田间试验中土著和接种根瘤菌菌株之间的竞争模式几乎没有影响。用放射性标记的白杨素和柚皮素进行的初步研究表明,对结瘤基因抑制剂的不同反应可能部分归因于每种菌株能够代谢植物类黄酮的程度。