Combating early blight infection by employing Bacillus subtilis in combination with plant fertilizers

Abstract

In sustainable agriculture, integrated plant nutrition management along with a biological agent is an imperative module as a cost-effective and eco-friendly approach against drastic plant hackers (phytopathogens). Bacillus subtilis is one of the most potential biological control agents, because of the broad-spectrum activity of their antibiotics. The current study was carried out to explore in vivo biocontrol efficacy of Bacillus subtilis alone and in combination with plant nutrients [NPK, Zn (1X & 2X), Mg and B] against early blight disease of tomato caused by the necrotrophic fungus Alternaria solani. Results revealed that foliar application of B. subtilis alone and in combination with the plant nutrients managed EB disease significantly by 67–83%, while improved plant growth attributes by 20–77%. B. subtilis and plant nutrients helped the tomato plant to fight off the plant hacker by up-regulating the production of total phenolic contents and defensive enzymes (phenylalanine ammonia-lyase, superoxide dismutase, catalase, peroxidase, and polyphenol oxidase). In the current investigation, the light was shed on the interactive effect of microbial agent and positive consequences on plant mineral uptake. It was concluded that integrative use of NPK and Zn (2X) along with B. subtilis have a synergistic impact to manage the disease, improve plant growth, and optimistically enhance physiological and biochemical attributes to contest EB stress in tomato plants. Keywords: Alternaria solani, Bacillus subtilis, Biocontrol agent, Early blight, Plant nutrients, Zinc