Utilization of endophytic bacteria as a biological control agent of fungal pathogens and its plant growth promoting activities solanum lycopersicum

Abstract

Bacterial endophytes are a class of microorganisms that are found in the inner part of plant, especially in the plant tissues without showing any detrimental effects on the plant growth and development. They are distributed widely and are found to be aiding plants growth and development by overcoming various biotic and abiotic stresses. The main aim of this study was to isolate endophytic bacteria as biological control agents against fungal pathogens and its utilization as plant growth promoters. For this, ten endophytic bacteria were isolated from the leaves of different tomato plants from JNU campus. Preliminary screening of all the isolates was carried out against tomato plant pathogens Alternaria alternata, ITCC 6134. The most promising strain was further subjected to molecular characterization by 16s rRNA analysis. The liquid Chromatography Mass Spectrometry technique showed the biological active compounds present in the bacterial exract of BBB3 which might have played role in inhibiting fungal growth. Different tests for enzymic activity like cellulase, phosphatase and heavy metal resistance (Mercury and Cadmium) were done. The in vivo plant growth promoting activities on tomato seedling and seeds were carried out in a greenhouse to observe the efficacy of isolated endophyte directly. The isolated bacteria coded BBB3 among ten showed the efficient fungal inhibition as it suppressed the pathogen invitro. BBB3 also showed the degradation of cellulose media, phosphate solubilization activity and resistance to a high concentration of Mercury and Cadmium. The greenhouse evaluations of the endophyte showed significant (p≤0.05) biological control efficacy, higher growth and yield components of tomato plant. Furthermore, the metabolomics profile of the active compound could be exploited for large scale production of natural and environmental friendly biological control agents for the replacement of synthetic chemical agents and directing towards sustainable agriculture.

Keywords:Endophytes, Heavy metal resistance, sustainable, plant growth promoter