Inactivation of seed exudate stimulants of Pythium ultimum sporangium germination by biocontrol strains of Enterobacter cloacae and other seed-associated bacteria

摘要: Abstract Strains of Enterobacter cloacae and other seed-associated bacteria, effective in suppressing Pythium seed rot damping-off, were tested for their ability to reduce the stimulatory activity (STA) plant exudates sporangia seed-rotting fungus, ultimum. Our results have shown that E. can utilize exudate from a number species as sole carbon energy source and, at same time, rapidly STA P. ultimum sporangia. At higher cell densities cloacae, was inactivated more than lower densities. Concentrates prepared cloacae-treated exudate, when added untreated did not compared with unamended indicating sporangium germination inhibitors are produced by during growth on cotton exudate. Bacteria, consisting largely Pseudomonas species, isolated seeds various species. Many bacterial strains could within 24 h amounts supporting less 20% Four 21 strain EcCT-501 reducing STA. When inactivate linoleic acid (a predominant stimulant found exudate), only one EcCT-501. A positive correlation (correlation coefficient=0.507) observed between levels inactivation bacteria Furthermore, negative coefficient=−0.423) seedling stands following treatment these strains. However, poor coefficient=0.270) consistent hypothesis inactivates metabolizing active molecules, including acid, present this trait is important biological control strain. traits may function among genera