EFFECT OF 2,4-DIACETYLPHLOROGLUCINOL PRODUCED BY Pseudomonas fluorescens Q2··87 ON P-1,3 GLUCANASE AND CELLULASE OF Pythium ultimum

Document Type : Original Article

Authors

1 Botany Department, Faculty of Agriculture, Suez Canal University, Ismailia, Egypt.

2 Horticulture Department, Michigan S.ate University, E, Lansing, MI 48824.

3 Plant Pathology Department, Michig~n State University, E. Lansing, MI48824

Abstract

In our previous study we demons' rated that the biocontrol agent,
Pseudomonas fiuorescens 02-87 producing the- antibiotic 2,4-diacetylphloroglucinol
(2,4·DAPG), has the ability to antagonize the phytopathogenic Pyfhium spp, by
degradation of hyphal cell walls and inhibition of growth. Thin-layer chromatography
(TLC)' as well as high performance liquid chromatography (HPLC) techniques were
used to confirm the production of 2,4·DAPG from the biocontrol agent P. fiuorescens
02·87. Activities of polysaccharide degrading Enzymes, ~·1 ,3 and p ·1,4 glucanase
(cellulase), and their relation to Pyfhium ultimum Trow cell wall degradation in relation
to exogenous application of 2,4·DAPG were investigated during the first 72 h after
treatment. Higher levels of ~ -qlucanases in treated P. ultimum comparing to that in
control were detected. Glucanase activity reached its highest peak at 12 h; however,
cellulase activity reached its highest peak at 24 h after application. Native
polyacrylamide gel electrophoresis also confirmed the activities of such hydrolytic
enzyme in treated Pyihium mycelia. Conclusior that bacterial cell-wall degrading
enzymes origin are excluded since 2,4·DAPG isolation procedure resulted in 2,4-
DAPG-free from such enzymes. The preser t results suggest that exogenous
application of 2,4·DAPG to Pythium resulted in higher levels of such cell-wall
degrading enzymes that participated in hyphal degradation of the oomycete Pythium

Keywords

Journal of Agricultural Chemistry and Biotechnology
Volume 29, Issue 2
February 2004
Pages 825-840

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