Aims: This study aimed to screen the plant growth-promoting fluorescent bacteria (FLB) which isolated from the healthy rice rhizophere and to evaluate its biocontrol and growth promotion properties against Pyricularia oryzae on aerobic rice seedling of MARDI Aerob 1. Methodology and results: King’s B agar with glycerol was used as the selective medium to isolate FLB from the healthy rice rhizosphere soil. All FLB obtained were in vitro screened for antagonistic activities against P. oryzae using dual culture, volatile substances and hydrogen cyanide productions. The potential FLB isolates were further evaluated on rice seedling early growth promotion before identified using 16S rRNA gene sequencing. A total of 24 FLB were isolated from the healthy rice rhizosphere soil in Setiu, Terengganu, Malaysia. Isolates: FLB4, FLB5, FLB7 and FLB10 scored the total of percentage inhibition radial growth (PIRG) values ranged 99.5-105.0%. Further seedling growth promotion screening revealed that FLB4, FLB7 and FLB10 were significantly improved seedling growth with vigor index of 378.32%, 461.53% and 335.60% over control (133.31%). 16S rRNA sequencing identified that FLB7 as Bacillus subtilis and the FLB4 and FLB10 as Pseudomonas putida. Conclusion, significance and impact of study The selected FLB isolates (FLB4, FLB7 and FLB10) are potential to be developed as biological control agents against P. oryzae with growth promoting property on aerobic rice seedling.
Plant Breeding--methods