Characterization of antifungal metabolite produced by a new strain Pseudomonas aeruginosa PUPa3 that exhibits broad-spectrum antifungal activity and biofertilizing traits.
OBJECTIVE
To study the antifungal activity and plant beneficial traits of a broad-spectrum antagonistic fluorescent pseudomonad strain, PUPa3.


RESULTS
Strain PUPa3 was isolated from the rhizosphere soil of rice and identified as Pseudomonas aeruginosa on the basis of biochemical tests and by comparison of 16S rDNA sequences. This bacterium exhibits a broad-spectrum antifungal activity towards phytopathogenic fungi. The antifungal metabolite by PUPa3 was extracted, purified and characterized using nuclear magnetic resonance (NMR) and mass spectroscopy (MS). Production of indole-3-acetic acid (IAA), siderophores, phosphatase and protease in PUPa3 was determined. Strain PUPa3 did not produce hydrogen cyanide, cellulase and pectinase.


CONCLUSIONS
The antifungal metabolite produced by PUPa3 has been identified as phenazine-1-carboxamide (PCN) on the basis of NMR and MS data. Strain PUPa3 showed a broad-spectrum antifungal activity towards a range of phytopathogenic fungi. This bacterium also showed several plant growth-promoting traits but did not show the traits attributed to deleterious rhizobacteria.


CONCLUSIONS
Present study reports the production of PCN as well as IAA for the first time by a saprophytic P. aeruginosa strain PUPa3. Because of the production of siderophore, growth hormone, protease and phosphatase and its innate fungicidal potential, this strain can be used as biofertilizer and antagonist against a range of phytopathogenic fungi that infect rice, groundnut, tobacco, chili, mango, sugarcane, tea, cotton and banana.
Kumar
R Sunish
RS
Department of Biotechnology, Pondicherry University, Kalapet, Pondicherry, India.
Ayyadurai
N
N
Pandiaraja
P
P
Reddy
A V
AV
Venkateswarlu
Y
Y
Prakash
O
O
Sakthivel
N
N
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification*; D005308:Fertilizers; D005516:Food Microbiology; D009682:Magnetic Resonance Spectroscopy; D012275:Oryza; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism*; D012337:RNA, Ribosomal, 18S / Q000032:analysis
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D005308:Fertilizers; D012337:RNA, Ribosomal, 18S