Abstract
With the aim of elucidating mechanisms behind bacteria-induced deleterious effects and differential cultivar responses to bacterial inoculations, wheat seedlings were subjected to various tests under gnotobiotic conditions. Inoculation with two deleterious Pseudomonas isolates, Å 112 (fluorescent) and Å 313 (nonfluorescent), induced leaf symptoms and shoot and root growth inhibition, while inoculation with growthneutral bacteria (Serratia liquefaciens andEscherichia coli) had no such effects. Deleterious effects were induced at low inoculum densities (<103 cells per plant), but required addition of nutrient broth in small amounts for consistency. Effects similar to those obtained with living inoculum could be induced by treating plants with sterile culture filtrates from isolate Å 313 or volatile bacterial metabolites from isolate Å 112. Wheat cultivars previously found to differ in their reaction to inoculation under non-sterile conditions, responded differentially to Å 112 and Å 313 also in the gnotobiotic assay. The results agree with the hypothesis that neither cultivar reaction nor the bacterial effects as such are mediated by interactions with an indigenous rhizosphere microflora.
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Åström, B., Gerhardson, B. Wheat cultivar reactions to deleterious rhizosphere bacteria under gnotobiotic conditions. Plant Soil 117, 157–165 (1989). https://doi.org/10.1007/BF02220708
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DOI: https://doi.org/10.1007/BF02220708