Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Pathogenicity And Biocontrol Potentials Of Bacillus Subtilis On Postharvest Cassava Root Rot Pathogens
by Alfred O. Ubalua, Onyegbula O. Doris and Mbadiwe Maureen Nwaoma

Abstract:
Many species of fungi are known to be associated with cassava root rot deterioration. These pathogens were isolated from the rots and reconfirmed through pathogenicity tests. Bacillus subtilis, a non-pathogenic organism with over 10-year history of commercial use as probiotic and as a biocontrol agent was our choice of antagonist. The inhibitory efficiency of this bio-agent was screened on the pathogens and four of the promising isolates were selected based on their suppressive activities and were subsequently identified as strain BA1, BA2, BA3 & BA4. Further investigation revealed that isolates BA2 & BA3 expressed more stable in vitro antagonism against Botryodiplodia theobromae (1.3�0.34, 1.5�0.13 cm), Aspergillus niger (1.7�0.15, 1.0�0.07 cm) and Fusarium spp. (1.4�0.33, 1.3�0.12 cm) respectively. Our result collectively, suggests that Bacillus subtilis strain BA2 & BA3 suppressed the pathogens through complex mechanisms including secretion of antimicrobial metabolites and aggressive colonization of the microsites of the roots parenchyma. __________________________________________________________________________________________ Keywords:

Keywords: Deterioration, Probiotic, Biocontrol, Antimicrobial Metabolites, Colonization, Microsites

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