Biocontrol of Citrus Canker Disease Caused by subsp. Using an Endophytic .

Citrus canker is a devastating disease of citrus caused by subsp. (). A total of 134 endophytic bacteria were isolated from various gymnospermic and angiospermic plants. They were screened for their antagonistic activities against three wild-type and six streptomycin-resistant strains. TbL-22 and TbL-26, both later identified as , inhibited all the wild and resistant strains. TbL-22 exerted the highest antagonistic activity against W3 and M6 with inhibition zones of 20.64 ± 0.69 and 19.91 ± 0.87 mm, respectively. Similarly ethyl acetate extract of TbL-22 showed highest inhibition zones 15.31 ± 2.08 and 19.37 ± 3.17 mm against W3 and M6, respectively. TbL-22 reduced canker incidence on infected leaves by 64.05% relative to positive controls. Scanning electron microscopy revealed that the cell membranes of treated with ethyl acetate extract of TbL-22 were ruptured, lysed, and swollen. TbL-22 can effectively and sustainably controls streptomycin-resistant citrus canker.