Isolation screening and characterisation of local beneficial rhizobacteria based upon their ability to suppress the growth ofFusarium oxysporumf. sp.radicis-lycopersiciand tomato foot and root rot

Local beneficial rhizobacteria were selected based upon their ability to control the fungus Fusarium oxysporum f. sp. radicis-lycopersici which causes crown and root rot of tomato. Seven out of 384 strains prevailed in multiple and dual cultures and were identified as Pseudomonas chlororaphis (one strain), Bacillus cereus (one strain), Serratia marcescens (three strains) and Serratia rubidaea (two strains), by sequencing the 16S rRNA or the 16S and 23S rRNA inter-spacer region. The seven selected rhizobacteria were tested for their biocontrol and growth-promoting effects in planta, and their antifungal properties in vitro. All strains significantly reduced disease severity under controlled conditions, in a gnotobiotic system and in pots. Moreover, one P. chlororaphis and one S. marcescens strain significantly decreased disease severity to the level of the healthy control under natural conditions in pots experiments. The inhibitory activity of bacterial liquid cultures' metabolites on the fungus was demons...