Poster: Education

Abs # 14: Jasmonic acid in wheat leaves: control of proteolytic and inhibitor protease activities

Presenter:	Casalongue, Claudia , casalong@mdp.edu.ar
Authors	Casalongue, Claudia  (A)   Segarra, Carmen  (A)   Pinedo, Marcela  (A)   Conde, Ruben  (A)
Affiliations:	(A): Instituto de Investigaciones Biologicas

We previously found that the extracellular serine protease activity of wheat leaf is involved in the defence of plant against the pathogenic fungus Septoria tritici. This activity is controlled by an extracellular germin-like protein (GLP), which inhibits serine proteases. To investigate the nature of the signals involved in the regulation of such activities, seedlings were treated with different chemical inductors. It was found that jasmonic acid increased the leaf extracellular serine protease activity of a resistant cultivar, but decreased that of a susceptible cultivar. These events comprised decreased and increased activity of the GLP-inhibitor, respectively. Thus, jasmonic acid mimics the action of Septoria tritici on plants from wheat cultivars bearing distinct susceptibility to septoriosis. Neither salicylic acid nor fungal elicitor affected the serine protease activity examined. These findings suggest that jasmonic acid is an essential component for the regulation of the protease-inhibitor system in wheat defence mechanism against septoriosis.