Isolation, purification and characterization of an antifungal molecule produced by Bacillus licheniformis BC98, and its effect on phytopathogen Magnaporthe grisea.
OBJECTIVE
Isolation of bacterial antagonist for use in the biological control of phytopathogenic fungi like rice blast fungus, Magnaporthe grisea, and to further purify and characterize the antifungal molecule produced by the antagonist.


RESULTS
Bacterial antagonist exhibiting highest antifungal activity against the rice blast fungus M. grisea was isolated from soil and identified as Bacillus licheniformis BC98. Besides M. grisea, the isolate also inhibited the growth of other phytopathogens such as Curvularia lunata and Rhizoctonia bataticola. Biologically active fractions were isolated from the culture filtrate and further fractionated by reverse-phase high-performance liquid chromatography (HPLC) enabling detailed structural characterization of a component of molecular mass 1035 Da. The active peptide was identified as surfactin after 500 MHz (1)H NMR analysis. Microscopic analysis of the effect of the antagonist on M. grisea revealed bulbous hyphae showing patchy and vacuolated cytoplasm when observed under the electron microscope.


CONCLUSIONS
The antagonistic lipopeptide secreted by B. licheniformis BC98 and identified as surfactin, induced morphological changes in M. grisea, inhibiting its further growth, and thus exhibiting fungicidal activity.


CONCLUSIONS
The antagonist inhibits germination of M. grisea, a potent rice phytopathogen, and therefore appears to be a potential candidate for control of rice blast disease.
Tendulkar
S R
SR
Department of Microbiology and Biotechnology Centre, The M.S. University of Baroda, Vadodara, India.
Saikumari
Y K
YK
Patel
V
V
Raghotama
S
S
Munshi
T K
TK
Balaram
P
P
Chattoo
B B
BB
D000898:Antibiosis / Q000502:physiology; D000935:Antifungal Agents / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D001407:Bacillus / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D020082:Magnaporthe / Q000187:drug effects / Q000502:physiology*; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D012275:Oryza / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D012988:Soil Microbiology
D000935:Antifungal Agents