Mechanisms of Action of Pseudomonas Fluorescens against Fusarium Oxysporum F. Sp Phaseoli in Vitro
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Date
2021
Authors
Gathu, R. Kahuthia
Muthoni, W
Mwangi, M
Waceke, J.W
Journal Title
Journal ISSN
Volume Title
Publisher
Researchjournali’s Journal
Abstract
French bean accounts for 61% of the total horticultural exports in Kenya. Fusarium oxysporum f. sp phaseoli
has been a major threat causing up to 30% yield loss. The objective of the study was to screen locally isolated
Pseudomonas fluorescens for ability to suppress growth of F. oxysporum in vitro. Pseudomonas fluorescens
and F. oxysporum were isolated on King’s B medium and Potato dextrose agar, respectively. Soil and diseased
plants were sampled from farmer’s field in Kirinyaga County, Kenya. Fungal inhibition tests were performed
using plate assay based on production of antimicrobial substances. Thirty four P. fluorescens were isolated of
which 12 isolates produced fluorescence pigment. Five of the 12 strains showed significant antifungal activity
(P˂0.05) against F. oxysporum compared to control. Isolate Pf1 significantly (P≤0.001) inhibited the mycelial
growth and scored 72.2% compared to control. With non-volatile compounds, Pf2 isolate scored the least
mycelial growth of (24.0±1.15 mm) compared to control (77.0 ±2.08 mm). Isolates Pf1 had the highest
inhibition against F. oxysporum with 69.8 and 64.5%when grown on iron deficient and iron fortified King’s B
medium, respectively. Pseudomonas isolates tested were found effective and suppressed F .oxysporum thereby
recommended for further evaluation under field conditions
Description
Article
Keywords
Antimicrobial substances, Isolates, Mycelial growth, Percentage inhibition