Dazzo F B, Napoli C A, Hubbell D H
Appl Environ Microbiol. 1976 Jul;32(1):166-71. doi: 10.1128/aem.32.1.166-171.1976.
Quantitative microscope techniques were utilized to examine the adsorption of rhizobial cells to clover root hairs. Adsorption of cells of noninfective strains of Rhizobium trifolii or infective R. meliloti strains to clover root hairs was four to five times less than that of the infective R. trifolii strains. Attachment of the rod-shaped bacteria to clover root cells occurred in a polar, end-on fashion. Viable or heat-killed R. trifolii cells precoated with a clover lectin having 2-deoxyglucose specificity had increased adsorption to clover roots. Adsorption of bacteria to roots was not increased if the clover lectin was inactivated by heat or 2-deoxyglucose treatment prior to incubation with R. trifolii. Adsorption of R. trifolii to clover root hairs was inhibited by 2-deoxyglucose (30 mM) but not by 2-deoxygalactose or alpha-D-glucose. Adsorption of R. meliloti cells to alfalfa root hairs was not affected by 2-deoxyglucose at that concentration. These results suggest that expression of host specificity in the Rhizobium-clover symbiosis involves a preferential adsorption of infective cells to clover root hairs through a 2-deoxyglucose-sensitive receptor site.
运用定量显微镜技术来检测根瘤菌细胞对三叶草根毛的吸附作用。三叶草无效菌株或苜蓿中华根瘤菌感染性菌株的细胞对三叶草根毛的吸附量比三叶草感染性菌株少四至五倍。杆状细菌以极性、端部相对的方式附着于三叶草根细胞。预先用具有2-脱氧葡萄糖特异性的三叶草凝集素包被的活的或热灭活的三叶草菌株细胞对三叶草根的吸附增加。如果在与三叶草菌株孵育之前，三叶草凝集素通过加热或2-脱氧葡萄糖处理而失活，细菌对根的吸附不会增加。2-脱氧葡萄糖（30 mM）可抑制三叶草菌株对三叶草根毛的吸附，但2-脱氧半乳糖或α-D-葡萄糖则无此作用。该浓度的2-脱氧葡萄糖对苜蓿中华根瘤菌细胞吸附苜蓿根毛没有影响。这些结果表明，根瘤菌与三叶草共生中宿主特异性的表达涉及感染性细胞通过2-脱氧葡萄糖敏感受体位点优先吸附到三叶草根毛上。
