title: Selective infection of maize roots by streptomycin-resistant Azospirillum lipoferum and other bacteria.
abstract: The percentage of low-level streptomycin-resistant (20 microgram/mL) bacteria in surface-sterilized or washed maize roots was more than a thousand times higher than that in soil populations. There was also a higher incidence of resistant bacteria in rhizosphere as compared with non-rhizosphere soil and bacteria isolated from maize roots were relatively tolerant to several other antibiotics. Azospirillum lipoferum was predominant in surface-sterilized roots of field-grown maize and was low-level streptomycin-resistant while most soil isolates were sensitive. Inoculation with A. brasilense isolated from wheat roots was unsuccessful in terms of establishment even when streptomycin-resistant strains were used. Unidentified causes of specific plant-bacteria affinities therefore transcend the role of antibiotic resistance in maize root infection.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development*; D004352:Drug Resistance, Microbial; D010935:Plant Diseases; D012231:Rhizobium / Q000187:drug effects / Q000254:growth & development*; D012988:Soil Microbiology; D013045:Species Specificity; D013307:Streptomycin / Q000494:pharmacology; D003313:Zea mays / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D013307:Streptomycin