BIOCONTROL OF FUSARIUM OXYSPORUM THROUGH ALTERATION IN ROOT EXUDATES OF MAIZE BY MICROBIAL INOCULATION.

The significance of root exudates has long been under estimated, presumably of being concealed in nature. Plant growth promoting rhizobacteria (PGPR) and compost inhabiting bacteria (CIB) interact with plant to regulate root exudation. Present study was conducted at Biochemistry Section, Ayub Agricultural Research Institute, Faisalabad, Pakistan during the year 2018 to check antifungal effect of PGPR and CIB tested against fungal pathogen, (Fusarium oxysporum) with maize crop. Root exudates were collected and analyzed by high performance laquid chromatography (HPLC) to get an insight of their chemical composition. Our results indicated that conidial germination of pathogen was significantly decreased while bacterial population enhanced by exudates of those plant roots which were treated with bacterial consortium. Analysis of root exudates revealed that composition of root exudates of co-inoculated plants, differ not only from the exudates of pathogen free plants but also from the un-inoculated controls referring to only pathogen inoculated plants. Salicylic acid (upto 83%), chlorogenic acid (upto 46%) and caffeic acid (upto 61%), along with higher quantities of malliec acid (upto 24%) were found in exudation of bacterial treated plants. The increase in concentration of specific secondary metabolites might have a role in inducing systemic resistance in the maize against seedling blight (Fusarium oxysporum). In conclusion, this study illustrates the disease resistance mechanism on the basis of plant-microbe communication and helps to devise suitable strategies against fusarium-mediated blight of maize plants. [ABSTRACT FROM AUTHOR]