Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/15/2006
Publication Date: 4/1/2007
Citation: Bacon, C.W., Hinton, D.M. 2007. Potential for Control of Seedling Blight of Wheat Caused by Fusarium graminearum and Related Species Using the Bacterial Endophyte Bacillus mojavensis. Biocontrol Science and Technology. 17:81-94. Interpretive Summary: Fusarium species infect grains and cereals causing billions of dollars in losses to the agricultural markets. F. graminearum-infected grain decreases seed germination and seedling emergence, cause post-emergence seedling death, Fusarium head blight, and reduce yield. The fungus also produces the mycotoxin DON. Current seed treatments are effective against surface fungi on grain but have limited effects on the control of systemic persistent fungal pathogens. A patented endophytic bacterium, Bacillus mojavensis, a species within one of the B. subtilis subgroups, was studied to determine its potential as an endophytic biocontrol for F. graminearum induced seedling blight of wheat. This bacterium was shown to be antagonistic in vitro to numerous fungi including F. graminearum. Data from plant growth room and greenhouse studies indicated that B. mojavensis inoculated kernels reduced all F. graminearum seedling colonization, increased the number of germinating seeds, rate of seed germination, and seedling root and shoot growth in all varieties tested.
Technical Abstract: Fusarium infected-wheat seed decreases germination, seedling emergence, and causes post emergence seedling death, and can contribute to wheat scab and ear rot of maize, with consequent production of mycotoxins such as deoxynivalenol and zearalenone. A patented endophytic bacterial strain, Bacillus mojavensis RRC 101, and several other strains of this species were studied to determine in vitro antagonism to some Fusarium species and to assess the potential of this bacterium to serve as an endophytic biocontrol for seedling blight of wheat produced by species within the F. graminearum complex, as well as other species of Fusarium. Seedling emergence and seed germination were two tests used as indicators of seedling blight. These tests were conducted in growth rooms with two wheat cultivars highly susceptible to scab, Norm and Pioneer 2552, and other cultivars with varying resistance to scab. The results indicated that all strains of this bacterium were antagonistic in vitro to the strains of F. graminearum and its seven related species, as well as four strains of F. pseudograminearum and the two strains of F. verticillioides. Germination of the highly scab susceptible cultivar 2552 was increased from 77% to 97% when planted in soil containing a mixed inoculum of F. graminearum and related species. Seedling emergence in the very susceptible wheat cultivar Norm increased from 20% to 82% when treated with the bacterium. The data indicated that inoculating wheat kernels with B. mojavensis reduced seedling blight of wheat produced by F. graminearum and related Fusarium species indicating the potential for this bacterium as a biocontrol under field condition.