Antagonism of Bacillus strains against phytopathogenic bacteria Xanthomonas citri pv citri

OLIVELLA, LAURA; BARENGO, PAMELA B.; GAIDO, J.; PIZARRO, DOLORES M.; ESPARIZ, MARTIN; DAURELIO, LUCAS D.

Congreso; Congreso conjunto SAMIGE-SAIB; 2020

SAMIGE-SAIB

Citrus is a worldwide fruit crop with high value for both fresh and processed fruit markets. However Asiatic citrus canker, caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xcc) is among the most economically damaging diseases affecting citrus industries. An alternative for canker disease management is to use antagonic bacteria. The aim of this work was to investigate the antagonistic activity of twelve Bacillus strains against Xcc. This activity was tested by diffusion assays. Liquid cultures of Xcc and twelve Bacillus strains (C1-C12) were grown in Luria Bertani (LB) medium with continuous agitation overnight and were diluted to an optical density (OD) of 1. Petri dishes were covered with 15 ml of LB-agar containing 100 µl of the Xcc dilution. First, a screening using a plate for each strain was performed by inoculating four drops of 2 µl of bacterial culture. This test was made in duplicate. After 2 days, the inhibition areas were observed. For the two strains that showed inhibition zones in both replicates, the experiment was repeated and the average inhibition area was calculated as IA = average area of the inhibition zone - average area of the colony. Significant inhibition areas of 2.475 cm2 for C5 and 2.435 cm2 for C11 were obtained (p