Structure, production characteristics and fungal antagonism of tensin - a new antifungal cyclic lipopeptide from Pseudomonas fluorescens strain 96.578.
OBJECTIVE
To study the antagonistic activity by Pseudomonas fluorescens strain 96.578 on the plant pathogenic fungus Rhizoctonia solani.


RESULTS
Strain 96.578 produced a new cyclic lipopeptide, tensin. High tensin production per cell was detected in liquid media with glucose, mannitol or glutamate as growth substrate while fructose, sucrose and asparagine supported low production. Tensin production was nearly constant in media with different initial C levels, while low initial N contents reduced production. When applied to sugar beet seeds, strain 96.578 produced tensin during seed germination. When challenged with strain 96.578 or purified tensin, Rhizoctonia solani reduced radial mycelium extension but increased branching and rosette formation.


CONCLUSIONS
The antagonistic activity of strain 96.578 towards Rhizoctonia solani was caused by tensin.


CONCLUSIONS
When coated onto sugar beet seeds, tensin production by strain 96.578 could be of significant importance for inhibition of mycelial growth and seed infection by Rhizoctonia solani.
Nielsen
T H
TH
Section of Genetics and Microbiology, Department of Ecology, The Royal Veterinary and Agricultural University, Copenhagen, Denmark. thn@kvl.dk
Thrane
C
C
Christophersen
C
C
Anthoni
U
U
Sørensen
J
J
D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000935:Antifungal Agents / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D019663:Chenopodiaceae / Q000382:microbiology; D003470:Culture Media; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D011551:Pseudomonas fluorescens / Q000378:metabolism*; D012232:Rhizoctonia / Q000187:drug effects / Q000254:growth & development*; D012639:Seeds / Q000382:microbiology
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D003470:Culture Media; D007783:Lactones; D010456:Peptides, Cyclic; C406010:cyclic lipoundecapeptide tensin