Mugineic acid-decomposing bacteria isolated from rhizoplane of iron-deficient barley
1989
Watanabe, S. (Tokyo Univ. (Japan). Faculty of Agriculture) | Wada, H.
Grasses have been found to endure iron-deficiency by excreting from their roots mugineic acids which are able to dissolve ferric compounds by forming Fe(III)-complexes. However, mugineic acids were suspected to be rather quickly decomposed by soil microorganisms. This means that mugineic acid-decomposing microorganisms, if present, will mitigate the beneficial effect of the mugineic acids. In addition, the relation between excretion of mugineic acids and mugineic acid-decomposing microorganisms is considered to be a simple model of the relation between plant roots and their rhizospheric microorganisms in general. According to these considerations, we searched for mugineic acid-decomposing microorganisms in the water-cultured iron-deficient barley. Microflora both in the cultural solution and on the root surface appeared to be fairly simple and composed of bacteria. Six strains of mugineic acid-decomposing bacteria were isolated from the barley roots. On the contrary, no mugineic acid-decomposing bacterium was isolated from the cultural solution. This result suggests that the mugineic acid-decomposing bacteria are liable to be adsorbed on the surface of roots. One strain of the bacteria,which could quickly decompose mugineic acid, was judged to belong to Pseudomonas, though no known species were identical with this strain
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