Colletotrichum acutatum PRODUCES A LOW MOLECULAR WEIGHT COMPOUND THAT SUPPRESSES-INDUCED DEFENSE

TOMAS GRAU, RODRIGO H; DIAZ RICCI, JUAN C.; REQUENA SERRA, FERNANDO J.; MARTOS, GUSTAVO G.

Córdoba

Congreso; SAIB 52º Anual Meeting; 2016

SAIB

AsES is a protein secreted by the isolate SS71 of Acremonium strictum that elicits a defense response in strawberry plants (Fragaria annanasa). Previously, we had observed that when plants were treated simultaneously with AsES and a conidial suspension of the pathogen Colletotrichum acutatum (isolateM11) a suppression of the AsES-induced response occurred. The aim of this work was to evaluate the defense suppression activity in plants of strawberry of the cv. Pájaro using a purified C. acutatum M11 supernatant (SNM11)extract by accumulation of ROS and phytopathological assays. Molecular weight estimation of the active compound was carried out by using a1KDa cut-off membrane. The probe DCFH-DA (2‗,7‗-dichlorodihydrofluorescein diacetate) was used for intracellular ROS detection in strawberry leaf discs treated with: i) SN-M11,ii) filtered SN-M11(SN-M11f) and iii) culture medium (PDB, as control). The suppression of the defense response was evaluated by phytopathological assays, infecting strawberry plants with active conidia of the virulent isolate M11 previously treated with: i) AsES, ii) SN-M11+AsES, iii) SN-M11f+AsES and iv) H2O2. Results showed that the active defense response suppressing compound was lower than 1 kDa; SN-M11f suppressed intracellular ROS accumulation and plants treated with SN-M11f were unable to activate the defense response induced by the elicitor AsES.