Accumulation of the compatible solutes, glycine-betaine and ectoine, in osmotic stress adaptation and heat shock cross-protection in the biocontrol agent Pantoea agglomerans CPA-2.
OBJECTIVE
The effect of modifying the water activity (a(w)) of Pantoea agglomerans growth medium with the ionic solute NaCl on water stress resistance, heat-shock survival and intracellular accumulation of the compatible solutes glycine-betaine and ectoine were determined.


RESULTS
The bacterium was cultured in an unmodified liquid medium or that modified with NaCl to 0.98 and 0.97 a(w), and viability of cells evaluated on a 0.96 a(w)-modified solid media to check water stress tolerance. Cells grown under ionic stress had better water stress tolerance than control cells. These cells also had cross-protection to heat stress (30 min, 45 degrees C). The modified cells accumulated substantial amounts of the compatible solutes glycine-betaine and ectoine in contrast to the control cells, which contained little or none of these two compounds.


CONCLUSIONS
Improvement in osmotic and thermal tolerance of cells of the biocontrol agent P. agglomerans by modifying growth media with the ionic solute NaCl was achieved. The compatible solutes glycine-betaine and ectoine play a critical role in environmental stress tolerance improvement.


CONCLUSIONS
This approach provides a method for improving the physiological quality of inocula and could have implications for formulation and shelf-life of biocontrol agents.
Teixidó
N
N
Postharvest Unit, CeRTA UdL-IRTA, Lleida, Catalonia, Spain. neus.teixido@irta.es
Cañamás
T P
TP
Usall
J
J
Torres
R
R
Magan
N
N
Viñas
I
I
D000222:Adaptation, Physiological; D000599:Amino Acids, Diamino / Q000378:metabolism*; D001622:Betaine / Q000378:metabolism*; D003470:Culture Media / Q000378:metabolism / Q000494:pharmacology; D005998:Glycine / Q000378:metabolism*; D006358:Hot Temperature; D009997:Osmotic Pressure; D020636:Pantoea / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D012965:Sodium Chloride / Q000378:metabolism / Q000494:pharmacology
D000599:Amino Acids, Diamino; D003470:Culture Media; D001622:Betaine; D012965:Sodium Chloride; C045628:ectoine; D005998:Glycine