This study evaluated the activity of a newly identified endophytic
actinobacterium strain Streptomyces rochei OM182844 as an antifungal
agent against soil-borne pathogenic fungi, Fusarium oxysporum f.sp.
cucumerinum, Sclerotinia rolfsii, and Pythium aphanidermatum. The
antifungal activity was performed using Strep. rochei culture and its crude
culture filtrate (CCF), and they showed superiority in the antagonistic activity
towards the three tested pathogens as inhibition of growth on plates and
reduction of mycelial growth weight in broth. Strep. rochei was a high
producer of cell-wall degrading enzymes (chitinases and cellulases) as a tool
used to degrade pathogenic fungal-cell walls. In addition, the released volatile
organic compounds (VOCs) were submitted for GC/MS analysis; it showed
that the most abundant compounds were Hexadecanoic acid, trimethylsilyl
ester (CAS) followed by iridomyrmecin which have antifungal activities.
Hence, the success of our idea of using actinobacteria isolated from healthy
plants as a biocontrol agent is a promising point for much research towards
the production of unconventional and environmentally safe biocides.