Biological Control of Alternaria Brassicae Causing Blight Disease of Brassica Juncea Through Microbial Consortium

Abstract

ABSTRACT newlineIndian mustard (Brassica juncea) commonly known as sarson is a protuberant oilseed crop newlinegrown worldwide which is rich in vitamins and proteins. Mustard crop is infected by several newlinefoliar diseases caused by soil borne pathogens, of which Alternaria blight incited by Alternaria newlinebrassicae is most prominent in Indian subcontinent. This disease limits the growth of the crop newlineand hence affect seed production. Management of blight disease majorly depends on chemicals newlinewhich have infinite negative effects on the environment. They directly or indirectly affect newlineliving beings by entering into food chain. An eco-friendly approach, like use of biological newlineagents is much safer and effective alternative to reduce the disease incidence. Use of biocontrol newlineagents has been gaining popularity in recent years as it not only works against the pathogen for newlinedisease suppression but also secrets metabolites and enzymes which help in the improvement newlineof plant growth. Therefore, this study was premediated to evaluate the potential of biocontrol newlinebacteria (PGPR) and biocontrol fungi (Trichoderma spp.) individually and in combination newlineagainst A. brassicae both in vitro and in vivo conditions. In this present investigation three newlinefungal and sixteen bacterial isolates were isolated from the rhizosphere soil. Fungal inhibition newlineassay of these isolated microbes was carried out against the pathogen in potato dextrose agar newlineplates and results were analysed after newline5 days of incubation. On the basis of fungal inhibition assay, two fungal (Th2, Th3) and two newlinebacterial isolates (B3, B12) were selected for further experiments. Secondary metabolites assay newlinewere also carried out of the selected isolates and their result show that all the four isolates newlinerelease secondary metabolites which inhibit the growth of A. brassiace and help in plant growth newlinepromotion of mustard plant. Biopriming of mustard seeds with all the four isolates was done newlineand they were assessed under greenhouse and field conditions, individually and in consortium.