Isolation and characterization of Pseudomonas brassicacearum J12 as an antagonist against Ralstonia solanacearum and identification of its antimicrobial components

Abstract

A bacterial strain, J12, isolated from the rhizosphere soil of tomato plants strongly inhibited the growth of phytopathogenic bacteria Ralstonia solanacearum. Strain J12 was identified as Pseudomonas brassicacearum based on its 16S rRNA gene sequence. J12 could produce 2,4-diacetylphloroglucinol (2,4-DAPG), hydrogen cyanide (HCN), siderophore(s) and protease. The maximum growth and antagonistic activity were recorded at 30°C and pH 8. Glucose and tryptone were used as the most suitable carbon and nitrogen sources, respectively. Strain J12 significantly suppressed tomato bacteria wilt by 45.5% in the greenhouse experiment. The main antimicrobial compound of J12 was identified as 2,4-diacetylphloroglucinol (2,4-DAPG) by HPLC-ESI-MS analysis. The gene cluster phlACBD, which is responsible for 2,4-DAPG production, was identified and expressed in the bacterial strain Escherichia coli DH5α.

Characterization of the antifungal and plant growth-promoting effects of diffusible and volatile organic compounds produced by Pseudomonas fluorescens strains

“…For instance, Serratia plymuthica showed multiple mechanisms in the biocontrol of diseases by B. cinerea and Sclerotinia sclerotiorum (Kamensky et al, 2003). Similarly, the Pseudomonas brassicacearum strain J12 produced diverse antifungal metabolites against Ralstonia solanacearum (Zhou et al, 2012), and Pseudomonas chlororaphis subsp. aurantiaca strain Pa40, which exhibited multiple mechanisms toward the suppression of sharp eyespot of wheat, caused by Rhizoctonia cerealis (Jiao et al, 2013).…”

Pseudopyronine B: A Potent Antimicrobial and Anticancer Molecule Isolated from a Pseudomonas mosselii

“…There are many reports of the production of antimicrobial metabolites by Pseudomonas spp. Some of these antimicrobials have been chemically characterized, and their commercial exploitation is attempted (Zhou et al, 2012). …”

Molecular Identification of 16S rDNA and Polyketide Synthase Genes of Antagonist Bacteria against Xanthomonas oryzae Pathovar oryzae from Rice Phyllosphere

“…Several examples that support this statement were the ability of Pseudomonas fluorescens against Xanthomonas oryzae (Shivalingaiah and Umesha, 2013), P. fluorescens 1100-6 against Rhizobium vitis causes tumors in wine (Eastwell et al, 2006), P. fluorescens and P. putida against P. solanacearum causes wilt disease in mulberry (Nuraeni and Fattah, 2007); P. rhizosphaerae JAN against Erwinia amylovora causes fire blight disease (Paternoster et al, 2010) and P. brassicacearum J12 against Ralstonia solanacearum causes bacterial wilt in tomatoes (Zhou et al, 2012).…”