Accumulation of the betaine and ectoine in osmotic stress adaptation of biocontrol agents against Fusarium verticillioides in maize”

SARTORI, MELINA; NESCI, A.; ETCHEVERRY, M.; MAGAN, N.

Edinburgo

Conferencia; IMC9: The Biology of Fungi.; 2010

International Mycological Asociation

Bacillus amyloliquefaciens and Microbacterium oelovorans have proved effectivity like biological control agents against Fusarium verticillioides in maize. Bacterial growth and survival at field are markedly affected by water availability. To reduce the internal water potential, bacteria are able to synthesize and to accumulate compatible solutes in response to environmental stress. The aim of this study was to determine the intracellular accumulation of the solutes betaine and ectoine in cells of B. amyloliquefaciens and M. oleovorans grown in triptic soy broth (TSB) media modified at 0.98, 0.97 and 0.96 aw with NaCl, glucose, glycerol and PEG 600, at 30°C for 24 h. B. amyloliquefaciens and M. oleovorans cells were resuspended skim milk, freezing at -20°C and then freeze-dried. Twenty five mg cell material was analized for intracellular amino acids betaine and ecotine, and cuantified by HPLC method. Cells grown under ionic solute stress showed accumulation of significant contents of both amino acids in all treatments. At 0.97 aw using NaCl resulted in a significant increase in both amino acids accumulation of biomass of M. oleovorans examined compared with control treatments. The tolerance of both bacteria to water potential modifications could increase the potential for biological control of F. verticillioides at field.