Submitted to: Aflatoxin Elimination Workshop Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 13, 2001
Publication Date: February 13, 2002
Technical Abstract: One strain of Bacillus mojavensis was shown to be a natural endophyte, dwelling within intercellular spaces of maize, providing protection against infections from other endophytic microorganisms such as the fungus Gibberella moniliformis. B. mojavensis is a relatively recently described bacterial species that is unique to desert soils and is distinguished by 16S rRNA sequence analysis. The major objective of this research was to determine the usefulness of ribosomal operon ribotyping as a means to differentiate among isolates of B. mojavensis from its closely related species, as well as distinguishing species diversity of B. mojavensis at the strain level. Another objective included characterizing the nature of antagonism expressed by B. mojavensis strains to G. moniliformis. An automated ribotyping instrument was used to generate several sets of ribotyping patterns. Four ribogroups (or ribotyping pattern groups) were detected among the 14 strains of B. mojavensis, and these were clearly distinct from related species. Ribotypes within strains of B. mojavensis indicated wide genetic diversity, and no strain had ribotypes charac-teristic of its desert origin. The study established that all 13 strains of B. mojavensis, isolated from major deserts of the world, are geneti-cally diverse, endophytically colonized maize and are antagonists to F. moniliforme. Results indicated that ribotyping can be used as a defini-tive way to categorize desert isolates of B. subtilis as B. mojavensis-like and that the large degree of genetic diversity expressed by dif-ferences in ribotyping of strains of this species might indicate wide applications of this species as a biological control agent of several pests.