Cyclic Depsipeptide Producing Fluorescent Pseudomonads Exerts Antifungal Activity against Fungal Pathogens of Maize (Zea mays)

Cyclic lipopeptides (CLPs) with antibiotic, biosurfactant producing fluorescent pseudomonads were
isolated from sugar beet-maize intercropped in sandy loam soils at Maize Research Station, Vagarai,
TNAU. Approximately 20 fluorescent pseudomonads from sandy loam soils were isolated by using
two different growth media. The strains were distinguished based on their growth, CFU/g,
fluorescence, and pigment production. Growth inhibition of maize pathogens by CLP producing
fluorescent pseudomonads strains were studied by dual culture experiments. The impact of CLP
producing flurorescent pseudomonads strain on the zoospores of Downy mildew pathogen of maize
was studied by direct microscopy and encysted zoospores were observed. Invitro, biochemical
experiments confirmed the presence of Viscosinamide producing strain among the fluorescent
pseudomonads isolates in terms of utilization of C and N sources. The particular strain was tested for
its growth promoting activity by treating the maize seeds for their germination, and seedling vigour
performance. Fluorescent pseudomonads can be affiliated to group under CLP producing
biotypes/biovars. Purification of CLP (Viscosinamide) and characterization by HPLC analysis was
carried out. Pot culture experiments were conducted to test the performance of CLP producing Pf
strains in maize crop for testing their disease resistance. These biovars with antibiotic properties are
the potential targets for the disease management in maize. CLPs in general receive considerable
attention as potent antimicrobial drugs.