Vol, 1(1) september 2016

Isolation, characterization and in-vitro screening of Actinobacterial isolates against Enset bacterial wilt pathogen (Xanthomonascampestrispv. musacearum)

Original Research Article

Kassahun Sadessa* and Tariku Hunduma

Ethiopian Institute of Agricultural Research
Ambo Plant Protection Research Center
Corresponding Author Email:ksbsedessa@yahoo.com


date Received: September 9, 2016     date Accepted: September 25, 2016     date Published: September 30, 2016

Abstract

Enseteventricosum is a perennial herbaceous plant considered as a food security crop in Ethiopia. More than 20% of Ethiopia’s population depends upon Enset for human food, fiber, animal forage, construction materials and medicines. However ,bacterial wilt disease of Enset (Xanthomonascampestrispv. musacearum) is the most important constraint of Enset productions. Even though, some management options have been practiced, yet no recommended effective control measures for Enset bacterial wilt disease are available. Thus, the aim of this study was to isolate, characterize and in-vitro evaluate Actinobacterial isolates as which are sources of antibiotics against Enset bacterial wilt pathogen. A total of 160 soil samples were collected from Toke Kutaye and Ambo districts of West Showa, Ethiopia were used as source material for the isolation of Actinobacteria. The soil samples were serially diluted up to 10-3 following which 0.1ml of serially diluted soil sample suspension was spread over starch casein agar selective medium (SCA) and Actinobacterial isolated. Actinobacteria were characterized morphologically based on colony morphology of the isolates such as on the bases of production of spore mass, the colour of the aerial mycelium (on the surface of agar), color of substrate mycelium color (underside of plate) and production of diffusible pigment. In addition, spore ornamentation was observed by a compound microscope. A total of 53distinct Actinobacteria isolates were recovered from 120 soil samples collected from croplands, forestlands and grazing lands. Actinobacterial isolates (36) showed bactericidal activity against Enset bacterial wilt pathogen in preliminary screening, 28 in dual culture and 18 in cell free suspension. Actinobacterial isolate Dhag-file130-1 was become the superior antagonist isolate followed by Awaro174-2, Awaro176-4,Senkel133-3 and Dhag-file113-2 which were 2, 2, 3 and 4respectively in their sequential order of decreasing of inhibition zone under mean separation against X. campestrispathogen. This study has indicated that Actinobacteria from the study areas have antagonistic activities against the tested pathogen. There can be a good potential for further investigation of bioactive Actinobacterial metabolites for further use from Ethiopian diversified ecology. The Actinobacterial isolates can be used as a component of integrated disease management after proofed and formulation of in-vivo assay. There is need to study the antagonistic properties of the isolates against other plant pathogens. In addition, the study should be extended to molecular based identification of the isolates and an in-depth structural analysis of their antibiotic compounds.


Key words:

Actinobacteria, Isolation, Characterization, Enset, Screening, Xanthomonascampestris


Isolation, characterization and in-vitro screening of Actinobacterial isolates against Enset bacterial wilt pathogen (Xanthomonascampestrispv. musacearum)