Study of the incompatible interaction between Colletotrichum fragariae and the cv. Pájaro of strawberry

SALAZAR, SERGIO MIGUEL; ARIAS, MARTA EUGENIA; TONELLO, URSULA; CASTAGNARO, ATILIO PEDRO; DIAZ RICCI, JUAN CARLOS

Pinamar. Argentina

Congreso; PABMB - 41º Annual Meeting SAIB; 2005

SAIB

We have previously reported that the cv Pájaro of strawberry presented a strong incompatible interaction with an avirulent isolate of C. fragariae. Macroscopic observations of leaves showed that, whereas a virulent isolate of C. acutatum used as control provoked a severe plant damage 10 days after the infection, the avirulent strain produced no damage, suggesting that a defense response was induced without the development of a hypersensitive response (HR). The aim of this work was to analyze microscopic events involved during the incompatible interaction and to investigate possible defense mechanisms supporting experimental observations. Microscopic studies showed that during the incompatible interaction, plant cells and leaf cuticle remain intact in contrast to the compatible interaction. Other conspicuous anatomic features were observed suggesting that plants undergo into a defense response. Molecular studies let us detect the expression of a glutathion S transferase that showed a 34 % identity with a tomato GST/GPX Bax inhibitor and by using DAPI (4’,6-diamidino-2-phenylindole) we have not detected PCD, suggesting that the induction of HR may be repressed by the BI-GST/GPX like protein detected in strawberry. This observation suggests that the ethylene defense signal pathway may be implicated.