Isolation, in vitro evaluation of Bacillus spp. against Fusarium oxysporum f.sp. ciceris and their growth promotion activity

Abstract

Background: Fusarium oxysporum f.sp. ciceris is one of the potential threats to chickpea cultivation as it causes greater a yield loss under favorable conditions. Management of this disease is difficult because of its soil-borne nature and also existence of races. Fungicide application is not economical and not practical. Application of antagonistic bacteria like Bacillus species is one of the best approaches for its management. Results: Ten Bacillus isolates were collected from healthy chickpea rhizosphere soil, identified and confirmed them as Bacillus based on the results obtained in Gram staining and biochemical characterization (up to species level). They were evaluated against Fusarium oxysporum f.sp. ciceris under in vitro conditions and selected two potential isolates (Bacillus-5 and Bacillus-7), screened for plant growth promotion properties and found thatBacillus-5 was able to solubilize phosphates, Bacillus-7 produced cellulases, both produced HCN and both were unable to produce IAA and chitinases. Identification of these two isolates was done by means of 16Sr DNA sequence analysis. Two universal primers such as 63F and 1387R were used which resulted in 1300 bp product. Blast analysis results indicated that they have more similarities with Bacillus cereus. Conclusions: Two potential Bacillus isolates out of 10 were selected based on in vitro assay and subjected to study for plant growth promotion characters and found thatBacillus-5 solubilizes phosphates, Bacillus-7 produced cellulases and both produced HCN. Based on 16S rDNA analysis, these potential antagonists have more similar sequences of Bacillus cereus. Further, field efficacy studies need to do in future.