Biochemical and Molecular Characterization of Bacterial Wilt Disease of Banana and Evaluation of their Antibiotic Sensitivity

Aims: Isolation and characterization of bacteria from the bacterial wilt disease of banana and evaluation of their sensitivity.

Study Design: This study was an experimental laboratory design.

Place and Duration of Study: Disease infected banana plant leaves were collected from Rajshahi University Campus, Rajshahi, Bangladesh in 2015 and the experiment had been conducted from 2015 to 2016.

Methodology: Two bacterial colonies were isolated (W1 and W2) and characterized by some morphological, biochemical and molecular test. Antibiotic sensitivity pattern was determined by disc diffusion method against the isolated bacteria. Molecular analysis were observed through the amplification of 16s ribosomal RNA primers and hrp gene specific primers (BXW-1/RST65 and BXW-3/RST69) and were cross reacted with other pathovars of Xanthomonas campestris, including X. campestris pv. musacearum strains.

Results: Isolated both two bacterial colonies (W1 and W2) were rod-shape, gram negative and motile, but W1 was yellow and W2 was creamy in color. Biochemical tests showed that both of them were catalase positive with addition to isolate W1 was MacConkey, citrate and TSI positive and SIM and urease negative whereas isolate W2 was MacConkey, citrate and urease positive, and SIM and TSI negative. In antibiotic sensitivity test among the five antibiotic (chloramphenicol, gentamycin, erythromycin, penicillin and ciprofloxacin), isolate W1 showed the highest susceptibility to penicillin and isolate W2 at gentamycin. In the molecular analysis, DNA from the isolated bacteria W1 showed approximately 1650bp band by using the 16s ribosomal primers 27-F and 1391-R. The presence of DNA sequence related to the hrp genes were successfully amplified by the isolate W1 which was related to X. campestris pv. musacearum.

Conclusion: As there is no effective research work on bacterial wilt disease of banana in Bangladesh, this work will be helpful for further direction of this devastating disease management.