Pseudomonas savastanoi pv. savastanoi (Psv) penetrates olive tissues through wounds and once inside plant tissue colonizes apoplast giving raise to knots formation. Little is known about the molecular signals early perceived in the apoplast by plant pathogenic bacteria, Psv included. Since Ca2+ is considered an important secondary messenger early involved in a number of bacterial processes, we determined in vitro changes in cytosolic Ca2+ levels in Psv (strain DAPP-PG722) cells, using the fluorescent probe FURA2AM. When bacterial cells were incubated in the absence of sugars, an increase in the cytosolic Ca2+ level coming from the extracellular medium was observed. A relationship between a possible energy deficiency state in the cells and Ca2+ signals was therefore hypothesized. Since the Ca2+ entry was inhibited by Li+ ions, employed in place of Na+, and nifedipine, an inhibitor of the L-voltage channels in mammals, we supposed the Ca2+ entry is mediated by an L-voltage Na+/Ca2+ exchanger. To demonstrate this hypothesis, we analysed in silico the genome of Psv strain DAPP-PG722 and a gene coding for a Na+/Ca2+ exchanger was found. In the relative mutant obtained the Ca2+ entry did not occur. Studies are in progress to characterise phenotypically the Psv mutant and to verify if the mutation affects the virulence of the bacterium.
CA2+ TRANSPORT IN PSEUDOMONAS SAVASTANOI PV: SAVASTANOI-OLIVE PATHOSYSTEM
MORETTI, Chiaraluce;GRANIERI, LETIZIA;CORTESE, CHIARA;MAZZONI, MICHELA;DEL PINO, Alberto Marco;BUONAURIO, Roberto;PALMERINI, Carlo Alberto
2015
Abstract
Pseudomonas savastanoi pv. savastanoi (Psv) penetrates olive tissues through wounds and once inside plant tissue colonizes apoplast giving raise to knots formation. Little is known about the molecular signals early perceived in the apoplast by plant pathogenic bacteria, Psv included. Since Ca2+ is considered an important secondary messenger early involved in a number of bacterial processes, we determined in vitro changes in cytosolic Ca2+ levels in Psv (strain DAPP-PG722) cells, using the fluorescent probe FURA2AM. When bacterial cells were incubated in the absence of sugars, an increase in the cytosolic Ca2+ level coming from the extracellular medium was observed. A relationship between a possible energy deficiency state in the cells and Ca2+ signals was therefore hypothesized. Since the Ca2+ entry was inhibited by Li+ ions, employed in place of Na+, and nifedipine, an inhibitor of the L-voltage channels in mammals, we supposed the Ca2+ entry is mediated by an L-voltage Na+/Ca2+ exchanger. To demonstrate this hypothesis, we analysed in silico the genome of Psv strain DAPP-PG722 and a gene coding for a Na+/Ca2+ exchanger was found. In the relative mutant obtained the Ca2+ entry did not occur. Studies are in progress to characterise phenotypically the Psv mutant and to verify if the mutation affects the virulence of the bacterium.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
