Interaction between serin and aspartic proteases involved in plant

SUELDO, DJ; ANDREU, AB; DALEO, GR; GUEVARA, MG Y OLIVIERI, FP.

Mar del Plata

Congreso; Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

In previous reports it has been showed that FESP, a Fusarium eumartii  extracellular serin protease, is able to degrade, in vitro, , a potato aspartic protease, StAP1, detected in intercellular washing fluids (IWF) after 1 day of wounding (1dW). Such interaction was analyzed in Pampeana, a cultivar susceptible to F. eumartii infection. In order to know the role of this interaction in the potato-F. eumartii pathosystem, the accumulation of both proteases was analyzed in Spunta, a moderately resistant cultivar. Results indicated that the pattern of accumulation of FESP and StAP1 in Spunta was similar to the one previously obtained in Pampeana, though the timing of expression differed, being StAP1 more persistent in Spunta than in Pampeana. On the other hand, in an attempt to determine if this proteolytic interaction affects StAP1 antimicrobial activity, F. eumartii conidia were incubated in the presence of StAP1 or StAP1 plus FESP and germination was evaluated. As expected, conidia failed to germinate when incubated with 3.75 uM StAP1, although they did in the presence of both proteases or FESP alone. This result show that the proteolytic interaction between StAP1 and FESP affects StAP1 inhibitory effect on F. eumartii conidia, suggesting a possible in vivo role, in which the StAP1 antimicrobial activity could be regulated by the accumulation of FESP in infected tissue.