Characterization of a Plant Growth-promoting Bacterium Burkholderia contaminans AY001 and Its Biological Control Activity

다국어 초록 (Multilingual Abstract)

Plant growth promoting (PGP) bacteria are enhancing plant growth and development through various mechanisms. In this study, Burkholderia contaminans AY001 was isolated from Agisan soil in Andong, South Korea. AY001 not only showed distinctive PGPR activities, such as N2-fixiation, phosphate-solubilization, extracellular protease production, zinc solubilization and indole-3-acetic acid (IAA) biosynthesis activities, but also anti-fungal activities against different plant pathogenic fungi, such as Fusarium oxysporum, F. avernaveum, F. solani, Colletotricum acutatum, Phytophthora capsici and Sclerotinia sclerotiorum. AY001 exhibited biological control activity against tomato Fusarium wilt disease caused by F. oxysporum f. sp. lycopersici (FOL) strain KACC 40038. In addition AY001 was effective in increasing the shoot and root weight in the tomato plants, thus demonstrating its PGP activity in vivo. AY001 treatment induced expression of induced systemic resistance (ISR) marker genes, such as, PIN2, LapA, ACO1, but also enhanced resistance against Pseudomonas syringae pv. tomato DC3000, suggesting its ISR inducing activity. Gas Chromatography-Tandem Mass Spectroscopy (GC-MS/MS) analysis of AY001 extracts identified potential antimicrobial compounds, including nonanal; pyrrolo[1,2-a]pyrazine-1,4-dione,hexahydro-3-(phenylmethyl) and pyrrolo[1,2-a]pyrazine-1,4-dione,hexahydro-3-(2-methylpropyl). Taken together, our newly isolated AY001 showed promising PGP and disease control activities, suggesting it can be successfully used as a potent biocontrol and biofertilizer agent in tomato plants.

목차 (Table of Contents)

• INTRODUCTION 1
• MATERIALS AND METHODS 5
• 1. Isolation and screening of the antagonistic bacteria 5
• 2. Molecular characterization of AY001 6
• 3. In vitro antagonistic activity assay 7
• 3.1. Dual culture and culture filtrate assays 7
• 4. In vitro plant growth promoting (PGP) activity assay 8
• 4.1. Zinc and phosphate solubilization activity 8
• 4.2. Protease production 9
• 4.3. Siderophore production 10
• 4.4. Indole-3-acetic acid (IAA) production 11
• 4.5. Ammonia (NH3) production 12
• 4.6. Nitrogen fixation 13
• 5. Plant growth promoting (PGP) and antagonistic effects of AY001 14
• 5.1. Plant growth condition and growth of FOL strain KACC 40038 and AY001 14
• 5.2. Inoculation method 15
• 5.3. Root colonization of AY001 16
• 6. Induced systemic resistance (ISR) against Pst DC3000 of AY001 17
• 6.1. Inoculation tomato plants with Pst DC3000 17
• 6.2. RT-PCR analysis of gene expression 18
• 7. Gas chromatography-tandem mass spectrometry (GC-MS/MS) Analysis 20
• RESULTS 21
• 1. Isolation and Identification of Burkholderia contaminans AY001 21
• 2. In vitro antagonistic activity assay 23
• 3. In vitro plant growth promoting (PGP) activity assay 26
• 3.1. Zinc and phosphate solubilization and Protease activity 26
• 3.2. Siderophore, ammonia and IAA production 28
• 3.3. Nitrogen fixation 29
• 4. PGP and antagonistic effect of AY001 in tomato plants 33
• 4.1. Antagonistic effect of AY001 on tomato Fusariun wilt disease 33
• 4.2. PGP effect of AY001 on tomato plants 34
• 4.3. Root colonization of AY001 37
• 5. ISR-inducing activity of AY001 in tomato plants 39
• 5.1. Quantitative analysis of Pst DC3000 in tomato plant leaves 39
• 5.2. RT-PCR analysis of gene expression 41
• 6. Gas chromatography-tandem mass spectrometry (GC-MS/MS) Analysis 43
• DISCUSSION 47
• REFERENCES 50
• ACKNOWLEDGMENT 60