Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa

A study was conducted to determine the antagonistic activity of epiphytic bacteria isolated from cocoa pod surface on Phytophthora palmivora (Butler) Butler, the causal agent of black pod disease of cocoa. Out of 233 isolates of epiphytic bacteria obtained from non symptomatic and diseased cocoa...

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Main Author: Mohd Jaaffar, Ahmad Kamil
Format: Thesis
Language:English
English
Published: 2004
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Online Access:http://psasir.upm.edu.my/id/eprint/41/1/1000548955_t_FP_2004_43.pdf
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spelling my-upm-ir.412013-05-27T06:45:13Z Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa 2004-10 Mohd Jaaffar, Ahmad Kamil A study was conducted to determine the antagonistic activity of epiphytic bacteria isolated from cocoa pod surface on Phytophthora palmivora (Butler) Butler, the causal agent of black pod disease of cocoa. Out of 233 isolates of epiphytic bacteria obtained from non symptomatic and diseased cocoa pods, only were found to have antagonistic activities against the fungal pathogen when screened by the dual-culture method. Three isolates, (LKM/B/1, LKM/B/35, LKM/B/76c) were identified as Pseudomonas putida Biotype A, 2 isolates (LKM/B/5 and LKM/B/62b) were identified as Pseudomonas aeruginosa and one isolate each was identified as Pseudomonas spinosa (LKM/B/2), Burkholderia glidioli (LKM/B/4) and Burkholderia sp (LKM/B/6). Identification of the epiphytic bacteria was done using the BIOLOG® Identification System. Percentage inhibition of the radial growth (PIRG) of P. palmivora by the epiphytic bacteria ranged from 66.0% to 82.1%. All isolates of epiphytic bacteria showed optimum antagonistic activities at 300 C. pH has no influence on the antagonistic activities of the epiphytic bacteria. Detached pod studies showed that pods treated with the epiphytic bacteria retarded the growth of black pod lesion up to 12 days after inoculation. Isolate Burkholderia glidioli (LKM/B/4), Pseudomonas aeruginosa (LKM/B/5) and Pseudomonas putida Biotype A (LKM/B/76c) produced volatile substances that affect the growth of P. palmivora, while isolates LKM/B/1 and LKM/B/35 of Pseudomonas putida Biotype A and isolate LKM/B62b of Pseudomonas aeruginosa did not show the production of volatile substances. Isolate LKM/B/76c also produced diffusible metabolites that could significantly inhibit the growth of P. palmivora compared to other epiphytic bacteria especially isolate LKM/B/35 which showed good antagonistic through dual culture method. Microscopic observations of P. palmivora at the periphery of the inhibition zone indicated that all isolates of epiphytic bacteria inhibited P. palmivora by the process of cell wall degradation and growth retardation. Fungal diseases of plants - Epidemics Phytophthora pod rot of cacao Antagonistic fungi 2004-10 Thesis http://psasir.upm.edu.my/id/eprint/41/ http://psasir.upm.edu.my/id/eprint/41/1/1000548955_t_FP_2004_43.pdf application/pdf en public masters Universiti Putra Malaysia Fungal diseases of plants - Epidemics Phytophthora pod rot of cacao Antagonistic fungi Faculty of Agriculture English
institution Universiti Putra Malaysia
collection PSAS Institutional Repository
language English
English
topic Fungal diseases of plants - Epidemics
Phytophthora pod rot of cacao
Antagonistic fungi
spellingShingle Fungal diseases of plants - Epidemics
Phytophthora pod rot of cacao
Antagonistic fungi
Mohd Jaaffar, Ahmad Kamil
Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa
description A study was conducted to determine the antagonistic activity of epiphytic bacteria isolated from cocoa pod surface on Phytophthora palmivora (Butler) Butler, the causal agent of black pod disease of cocoa. Out of 233 isolates of epiphytic bacteria obtained from non symptomatic and diseased cocoa pods, only were found to have antagonistic activities against the fungal pathogen when screened by the dual-culture method. Three isolates, (LKM/B/1, LKM/B/35, LKM/B/76c) were identified as Pseudomonas putida Biotype A, 2 isolates (LKM/B/5 and LKM/B/62b) were identified as Pseudomonas aeruginosa and one isolate each was identified as Pseudomonas spinosa (LKM/B/2), Burkholderia glidioli (LKM/B/4) and Burkholderia sp (LKM/B/6). Identification of the epiphytic bacteria was done using the BIOLOG® Identification System. Percentage inhibition of the radial growth (PIRG) of P. palmivora by the epiphytic bacteria ranged from 66.0% to 82.1%. All isolates of epiphytic bacteria showed optimum antagonistic activities at 300 C. pH has no influence on the antagonistic activities of the epiphytic bacteria. Detached pod studies showed that pods treated with the epiphytic bacteria retarded the growth of black pod lesion up to 12 days after inoculation. Isolate Burkholderia glidioli (LKM/B/4), Pseudomonas aeruginosa (LKM/B/5) and Pseudomonas putida Biotype A (LKM/B/76c) produced volatile substances that affect the growth of P. palmivora, while isolates LKM/B/1 and LKM/B/35 of Pseudomonas putida Biotype A and isolate LKM/B62b of Pseudomonas aeruginosa did not show the production of volatile substances. Isolate LKM/B/76c also produced diffusible metabolites that could significantly inhibit the growth of P. palmivora compared to other epiphytic bacteria especially isolate LKM/B/35 which showed good antagonistic through dual culture method. Microscopic observations of P. palmivora at the periphery of the inhibition zone indicated that all isolates of epiphytic bacteria inhibited P. palmivora by the process of cell wall degradation and growth retardation.
format Thesis
qualification_level Master's degree
author Mohd Jaaffar, Ahmad Kamil
author_facet Mohd Jaaffar, Ahmad Kamil
author_sort Mohd Jaaffar, Ahmad Kamil
title Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa
title_short Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa
title_full Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa
title_fullStr Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa
title_full_unstemmed Antagonistic Activities of Epiphytic Bacteria on Black Pod Disease of Cocoa
title_sort antagonistic activities of epiphytic bacteria on black pod disease of cocoa
granting_institution Universiti Putra Malaysia
granting_department Faculty of Agriculture
publishDate 2004
url http://psasir.upm.edu.my/id/eprint/41/1/1000548955_t_FP_2004_43.pdf
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