Abstract: To understand the colonization and distribution of Beauveria bassiana in maize and the effects of different application methods and concentrations on the growth and development of maize, the colonization of B. bassiana in the roots, stems and leaves of maize was observed by confocal laser scanning microscope using green fluorescent protein (GFP)-labeled B. bassiana. Our results showed obvious differences in the colonization of B. bassiana in different tissues of maize. The number of spores colonized in leaves was the highest, while no spores were observed in the stem area; a small number of spores was observed in the roots of maize that were treated only by seed soaking and root-irrigation treatments. The inoculation methods showed a great influence on the colonization rate of B. bassiana in maize. The highest colonization rate of 76.7% occurred in root-irrigation treatment, followed by seed soaking treatment (73.3%), while colonization rates were lower in foliar spraying and stem injection treatment (43.3% and 36.7%, respectively). In conclusion, different inoculation methods and dosages of B. bassiana suspension have certain effects on growth of maize, and B. bassiana can colonize and spread in maize and promote the growth and development of maize, with seed soaking and root irrigation at 1×10⁶-1×10⁷ spores/mL being the optimal methods.

Key words: green fluorescent protein (GFP), Beauveria bassiana, Zea mays, colonization