Ultrastructure of Rhizobium-induced infection threads in clover root hairs.
نویسندگان
چکیده
Ultrastructural studies of Rhizobium-induced infection threads in clover root hairs show that the infection thread is initiated by an invagination process. Root hair wall growth is redirected at a localized point, resulting in the formation of an open pore. There is no direct penetration through the wall, and the bacteria remain extracellular within the root hair.
منابع مشابه
Ultrastructure of Rhizobium-Induced Infection Threads in Clover Root Hairs1
The first stage in the establishment of the Rhizobium-legume symbiosis is the infection of the root of the host legume by the appropriate Rhizobium species. A recent and complete review of the infection process has been given by Dart (1). In the clover symbiosis, infective strains of Rhizobium trifolii enter the host through root hairs. A characteristic deformation is curling at the root hair t...
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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-o...
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Either NO(3) (-) (16 millimolar) or NH(4) (+) (1 millimolar) completely inhibited infection and nodulation of white clover seedlings (Trifoliin repens) inoculated with Rhizobium trifolii. The binding of R. trifolii to root hairs and the immunologically detectable levels of the plant lectin, trifoliin, on the root hair surface had parallel declining slopes as the concentration of either NO(3) (-...
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Infection of alfalfa with Rhizobium meliloti exo mutants deficient in exopolysaccharide results in abnormal root nodules that are devoid of bacteria and fail to fix nitrogen. Here we report further characterization of these abnormal nodules. Tightly curled root hairs or shepherd's crooks were found after inoculation with Rm 1021-derived exo mutants, but curling was delayed compared with wild-ty...
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ورودعنوان ژورنال:
- Applied microbiology
دوره 30 6 شماره
صفحات -
تاریخ انتشار 1975