Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2001
Publication Date: N/A
Interpretive Summary: A species of Bacillus subtilis, was reclassified using molecular techniques and found to be a strain of the very recently created Bacillus mojavensis. This strain was the patented strain that is useful in controlling plant diseases and reducing the number of animal toxins produced by specific fungi, especially Fusarium moniliforme. In this paper we compare the characteristics of our patented strain with those of other isolates of B. mojavensis, as well as other species within this family of bacteria. A total of seven other species within this family and 13 strains of B. mojavensis were tested for their ability to colonize plants internally and deter the growth of F. moniliforme. We established that all 13 strains of B. mojavensis were endophytic and could deter the growth of the fungus. The abilities of the other six species within this family of bacteria varied in their ability to either deter the growth of the fungus or internally infect plants. We concluded that the biological association of B. mojavensis with plants and the ability to antagonize fungi are characteristics of this species and that this bacterium, found in desert soils of the world, is a natural biocontrol with high biocontrol potential.
Technical Abstract: The identity of a patented endophytic bacterium was established by 16S rRNA sequence analysis as a strain of Bacillus mojavensis, a recently erected species within one of the B. subtilis subgroups. This strain of B. mojavensis is antagonistic to the fungus Fusarium moniliforme, an endophytic mycotoxin producing pathogen of maize and other plants. There are five other species within this subgroup: Bacillus amyloliquefaciens, B atrophaeus, B. licheniformis, Brevibacterium halotolerans, Paenibacillus lentimorbus, and P. popilliae. The objectives of this research were to screen other isolates of B. mojavensis, B. subtilis, and the other closely related Bacillus species for endophytic colonizing ability, and to determine the in vitro antagonism to F. moniliforme in an effort to survey the distribution of desirable biocontrol qualities within the Bacillaceae. Antagonism was determined on nutrient agar and endophytic colonization was established with maize plants following recovery of rifampin-resistant mutants generated from all strains used in the study. The study established that all 13 strains of B. mojavensis, isolated from major deserts of the world, were capable of the endophytic colonization of maize, and were antagonists to F. moniliforme. The endophytic colonization of maize by B. subtilis and other species within this subgroup of the Bacillaceae varied, as well as the ability to antagonize F. moniliforme. Thus, this study established that endophytic colonization is another characteristic of the species B. mojavensis. This characteristic and antagonism to the test fungus suggest that isolates of this species might prove to be important biocontrol organisms where the endophytic habit is desired.