Characterization of a <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis> strain from tomato rhizosphere and its use for integrated management of tomato damping-off |
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Authors: | Jayaraman Jayaraj T Parthasarathi N V Radhakrishnan |
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Institution: | (1) Department of Plant Pathology, Faculty of Agriculture, Annamalai University, Annamalai nagar, Chidambaram, 608 002, Tamil Nadu, India;(2) Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6;(3) Department of Agriculture, Government of Tamil Nadu, Chennai, India;(4) Department of Plant Pathology, Coconut Research Station, Kerala Agricultural University, Balaramapuram, Thiruvananthapuram, 695 509, Kerala, India |
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Abstract: | A highly antagonistic Pseudomonas fluorescens strain was isolated from tomato rhizosphere and characterized for its in vitro and in vivo biocontrol potential against Pythium aphanidermatum. The identified Pseudomonas fluorescens strain (PfT-8) was capable of producing high levels of chitinase, β-1,3-glucanase, cellulase, fungitoxic metabolites and
siderophores. Seven different carrier formulations including a talc-based powder, lignite-based powder, peat-based powder,
lignite + fly ash-based powder, wettable powder, bentonite-paste and polyethylene glycol (PEG) paste were prepared utilizing
PfT-8. Shelf life was evaluated for up to 6 months of storage at ambient room temperature (28 °C). Biocontrol efficacy of
formulations was studied under greenhouse and field conditions. The formulations were stable up to at least 2 months of storage
at ambient room temperature. Among the formulations, peat, lignite, lignite+fly-ash and bentonite paste based formulations
maintained higher propagule number than others and also showed greater biocontrol potential. However, propagule number gradually
decreased with time. Several organic amendments including farm yard manure (FYM), leaf-compost, poultry manure, press mud,
vermi-compost and neem cake were incorporated into soil to study their influence on P. fluorescens colonization in the rhizosphere and on potential disease control. Soil incorporation of organic amendments and specifically
poultry manure and FYM, significantly reduced damping-off incidence and also augmented the rhizosphere population of the marked␣P.␣fluorescens strain that was resistant to streptomycin and rifampicin. An integrated␣approach of damping-off management employing dual
inoculation of PfT-8 in seed and soil coupled with soil application of organic amendments including poultry manure or␣FYM
was evaluated under field conditions. Under these conditions, damping-off incidence substantially reduced by up to 90% and
further the healthy plant stand, plant biomass and plant rhizosphere population of P. fluorescens increased significantly. |
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Keywords: | carrier formulations integrated management organic amendments Pseudomonas fluorescens rhizosphere population tomato damping-off |
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