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. 1987 Dec;53(12):2793–2799. doi: 10.1128/aem.53.12.2793-2799.1987

Identification and Characterization of Rhizosphere-Competent Bacteria of Wheat †

M Elliott Juhnke 1,‡,*, D E Mathre 1, D C Sands 1
PMCID: PMC204200  PMID: 16347496

Abstract

To obtain rhizosphere-competent bacteria which could subsequently be modified for the development of biological control agents, bacteria were isolated from the rhizosphere and rhizoplane of wheat and barley plants by standard techniques. Of these isolates, 60 were selected for field testing as spring wheat seed inoculants in 1985. Isolates were marked genetically for resistance to antibiotics via selection of spontaneous mutants to detect and monitor isolates in the field. Forty-three days after planting, the average log10 CFU/mg (dry weight) of roots and rhizosphere soil for the mutant isolates sampled ranged from 0 to 3.4. Twenty mutant isolates were retested in 1986. A total of 4 isolates were not detected, but the other 16 had an average root colonization value of log10 2.1 CFU and a range of log10 0.9 CFU to log10 3.2 CFU when sampled 32 days after planting. The average colonization value dropped to log10 1.1 CFU 51 days later. Some isolates detected previously were not detected in the second sampling; others had root colonization values similar to those obtained in the first sampling. Mutant isolates of rhizosphere bacteria included Bacillus pumilus, Bacillus subtilis, Pseudomonas fluorescens, Streptomyces spp., Xanthomonas maltophilia, and a saprophytic coryneform. Mixtures of isolates from different genera and species were compatible on seeds and roots.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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