Characterization of Pantoea ananatis isolates and reaction of maize genotypes to the bacterium

ABSTRACT Maize white leaf spot, caused by the bacterium Pantoea ananatis, is one of the main leaf diseases affecting this crop. Using varieties resistant to the bacterium is the best strategy for the disease management. Thus, the aims of this study were to characterize and identify Pantoea ananatis isolates and evaluate maize hybrids resistant to this bacterial disease. The bacterium was isolated from maize leaves showing symptoms of water-soaked lesions. The bacterial isolates UFU A18 (Morrinhos-GO) and UFU B13 (Planaltina-GO) were identified based on cultural, biochemical and molecular characteristics, and pathogenicity in maize plants. The maize hybrids encoded as A1, A2, B1, B2 and B3 were inoculated with two bacterial isolates. The experiment was conducted in a greenhouse in randomized block design and factorial scheme (2 isolates x 5 hybrids) with six replicates. Disease severity was calculated on four evaluations, using a rating scale ranging from 0 to 4 and calculating the area under the severity progress curve. Bacterial isolates were identified as Pantoea ananatis and the maize hybrid A1 was resistant to the bacterium when inoculated with the bacterial isolate UFU B13.