Effectiveness of multi-trait Burkholderia contaminans KNU17BI1 in growth promotion and management of banded leaf and sheath blight in maize seedling.

Plant growth promoting (PGP) bacteria enhance plant growth and are a green alternative to chemical fertilizers. In our study, an effective plant growth promoting rhizobacteria (PGPR) strain, KNU17BI1, was isolated from rhizospheric soil of maize, South Korea. The strain was tested in vitro for specific PGP and antifungal traits, such as phosphate solubilization, zinc solubilization, indole acetic acid (IAA) production, ammonia production, nitrogen fixation, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, siderophore hydrogen cyanide production (HCN) and hydrolytic enzyme activity. Furthermore, in viro antifungal activity was done in a laboratory and in vivo effect of KNU17BI1 on banded leaf and sheath blight intensity as well as plant growth promotion on maize seedling were conducted under greenhouse conditions. The strain was found to be highly effective toward all the parameters except HCN production. The strain KNU17BI1 was identified on the basis of 16S RNA and multilocus sequence analysis (MLSA) and confirmed as Burkholderia contaminans. This study for the first time demonstrated potent in vitro antifungal activity of B. contaminans against Rhizoctonia solani AG-1(IA), Pythium graminicola, Fusarium moniliforme, Alternaria alternata, Alternaria solani, Fusarium graminearum, Stemphylium botryosum Wallr, Colletotrichum dematium, Stemphylium lycopersici and Fusarium oxysporum f.sp. melonis. Furthermore, in this study, for the first time, the potential of B. contaminans stain KNU17BI1 in controlling banded leaf and sheath blight of maize caused by R. solani AG-1(IA) was reported. Therefore, further studies are warranted on the structural identification of actual compounds behind such activities that would be exploited further for biocontrol as well as plant growth promotion.