ISHS Acta Horticulturae 225: Bacterial and Bacteria-like Contaminants of Plant Tissue Cultures
STRATEGY FOR THE SELECTION OF ANTIBIOTICS FOR USE AGAINST COMMON BACTERIAL PATHOGENS AND ENDOPHYTES OF PLANTS |
| Author: | F.R. Falkiner |
| Abstract:
Control of bacterial contamination in any area, including plant tissue culture, depends in the first instance on strict aseptic technique, sterilised equipment and media and an adequately decontaminated environment. The use of antibiotics should not be relied upon to allow compromise in routine asepsis. The contamination which will arise will often be due to resistant bacteria. Sometimes cryptic contamination and development of L-forms may occur. However, there is considerable scope for the use of antibiotics as an auxiliary safety measure in case of accidental contamination. For convenience we will term this prophylaxis. Naturally there is also the important aspect of therapeutic use of antibiotics to treat systemically, infected plant tissue. In both prophylaxis and therapy the effect of the in vitro conditions on the antibiotic must be assessed and appreciated. Changes in pH and presence of magnesium and calcium ions are examples. In therapy, adequate levels of the antibiotic must be achieved at the site of infection without damage to the host tissue. There have been reports, cited by Dodds and Roberts (1986), of some antibiotics or their derivatives altering the growth and development of plant tissue grown in vitro. In response to this problem there appears to be a search on for mutant plant tissue resistant to antibiotics, particularly the aminoglycosides such as streptomycin, kanamycin and gentamicin and the chemotherapeutic agent chloramphenicol. All of these act on the 30 S or 50 S ribosome subunits and seem to be reasonable choices for the prevention and treatment of plant tissue infection. To take into account the possible effects of the highly nutritious media it is important to perform the sensitivity tests and determine minimal bactericidal concentrations (MBC) using these media. In this paper some of the technical complications of selecting suitable antibiotics and the theoretical considerations that are involved, will be discussed. | |
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