Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan

Harumanis mango is one of the most popular fruits in Malaysia and has excellent potential as an export crop. The major pre and postharvest disease of mango is anthracnose, caused by the fimgus C. gloeosporioides. Synthetic fungicides are commonly used to reduce losses from anthracnose disease. Howev...

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Main Author:	J.Langkan, Falex
Format:	Thesis
Language:	English
Published:	2015
Subjects:	Medicinal plants (Culture only) Fruit and fruit culture
Online Access:	https://ir.uitm.edu.my/id/eprint/15408/1/TM_FALEX%20J.%20LANGKAN%20AS%2015_5.pdf
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id	my-uitm-ir.15408
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spelling	my-uitm-ir.154082023-01-31T08:35:10Z Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan 2015 J.Langkan, Falex Medicinal plants (Culture only) Fruit and fruit culture Harumanis mango is one of the most popular fruits in Malaysia and has excellent potential as an export crop. The major pre and postharvest disease of mango is anthracnose, caused by the fimgus C. gloeosporioides. Synthetic fungicides are commonly used to reduce losses from anthracnose disease. However, their use gradually become more restricted due to public concern over toxic residues. The aims of this study were to isolate the causal agent of antracnose and the antagonistic bacteria from the Harumanis mango, determine the antagonist activity of antagonist bacteria towards C. gloeosporioides in vitro, identifying the pathogen and the antagonist bacteria by 16S rDNA and screening the antifungal compounds produced by the antagonist bacteria. Twelve bacterial isolates were initially selected from 96 isolates tested which showed inhibitory effects against C. gloeosporioides on Potato Dextrose Agar (PDA). The mean PIRG (%) of the twelve potential bacterial antagonists were tested using Minitab statistical analysis software which showed that there was a significant difference in mean PIRG (%) with a ratio of 76.81 and an associated p-value of 0.000. Out of the twelve tested bacteria, two isolates, BT12 and BT09 had a significantly higher antagonistic activity against C. gloeosporioides. By using the 16S rRNA technique, isolates BT12 and BT09 were identified as Pseudomonas aeruginosa and Bacillus subtilis while the causal agent of Harumanis mango anthranose was identified as C. gloeosporioides. Both P. aeruginosa and B.subtilis strongly inhibited the fiingal growth by an average of 58.82% and 52.55% and rated at scale 3 using the growth inhibition scale (GIC). Malformation of the fiingal hyphae occurred in the presence of both bacteria which were viewed under light microscopy (LM) and scanning electron microscopy (SEM). Varying degrees of antagonistic effects occurred in the dual culture assay which included the production of antifungal compounds by the antagonist bacteria. The compounds were screened by gas chromatography mass spectrometry (GC-MS). Results indicated that P.aeruginosa and B. subtilis produced antibiotics such as Pyrrolo [1, 2-a] pyrazine-1, 4-dion, hexahydro-, Propanoic acid and Cylohexane, (1, 1-dymethylprophyl) which are responsible for the inhibition of fungal growth. Therefore, in vitro activities of the P.aeruginosa and B. subtilis against C. gloeosporioides of Harumanis mango in thisstudy suggested that the bacteria can be an effective biological control agent. 2015 Thesis https://ir.uitm.edu.my/id/eprint/15408/ https://ir.uitm.edu.my/id/eprint/15408/1/TM_FALEX%20J.%20LANGKAN%20AS%2015_5.pdf text en public mphil masters Universiti Teknologi MARA Faculty of Applied Sciences
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
topic	Medicinal plants (Culture only) Fruit and fruit culture
spellingShingle	Medicinal plants (Culture only) Fruit and fruit culture J.Langkan, Falex Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan
description	Harumanis mango is one of the most popular fruits in Malaysia and has excellent potential as an export crop. The major pre and postharvest disease of mango is anthracnose, caused by the fimgus C. gloeosporioides. Synthetic fungicides are commonly used to reduce losses from anthracnose disease. However, their use gradually become more restricted due to public concern over toxic residues. The aims of this study were to isolate the causal agent of antracnose and the antagonistic bacteria from the Harumanis mango, determine the antagonist activity of antagonist bacteria towards C. gloeosporioides in vitro, identifying the pathogen and the antagonist bacteria by 16S rDNA and screening the antifungal compounds produced by the antagonist bacteria. Twelve bacterial isolates were initially selected from 96 isolates tested which showed inhibitory effects against C. gloeosporioides on Potato Dextrose Agar (PDA). The mean PIRG (%) of the twelve potential bacterial antagonists were tested using Minitab statistical analysis software which showed that there was a significant difference in mean PIRG (%) with a ratio of 76.81 and an associated p-value of 0.000. Out of the twelve tested bacteria, two isolates, BT12 and BT09 had a significantly higher antagonistic activity against C. gloeosporioides. By using the 16S rRNA technique, isolates BT12 and BT09 were identified as Pseudomonas aeruginosa and Bacillus subtilis while the causal agent of Harumanis mango anthranose was identified as C. gloeosporioides. Both P. aeruginosa and B.subtilis strongly inhibited the fiingal growth by an average of 58.82% and 52.55% and rated at scale 3 using the growth inhibition scale (GIC). Malformation of the fiingal hyphae occurred in the presence of both bacteria which were viewed under light microscopy (LM) and scanning electron microscopy (SEM). Varying degrees of antagonistic effects occurred in the dual culture assay which included the production of antifungal compounds by the antagonist bacteria. The compounds were screened by gas chromatography mass spectrometry (GC-MS). Results indicated that P.aeruginosa and B. subtilis produced antibiotics such as Pyrrolo [1, 2-a] pyrazine-1, 4-dion, hexahydro-, Propanoic acid and Cylohexane, (1, 1-dymethylprophyl) which are responsible for the inhibition of fungal growth. Therefore, in vitro activities of the P.aeruginosa and B. subtilis against C. gloeosporioides of Harumanis mango in thisstudy suggested that the bacteria can be an effective biological control agent.
format	Thesis
qualification_name	Master of Philosophy (M.Phil.)
qualification_level	Master's degree
author	J.Langkan, Falex
author_facet	J.Langkan, Falex
author_sort	J.Langkan, Falex
title	Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan
title_short	Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan
title_full	Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan
title_fullStr	Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan
title_full_unstemmed	Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan
title_sort	antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / falex j.langkan
granting_institution	Universiti Teknologi MARA
granting_department	Faculty of Applied Sciences
publishDate	2015
url	https://ir.uitm.edu.my/id/eprint/15408/1/TM_FALEX%20J.%20LANGKAN%20AS%2015_5.pdf
_version_	1783733389301383168

Antagonistic activity of selected bacteria against colletotrichum gloeosporioides in harumanis mango / Falex J.Langkan

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