Colletotrichum acutatum produce a low molecular weight compound that suppress AsES-induced defense response

TOMAS GRAU, RODRIGO HERNÀN; MARTOS, GG; REQUENA-SERRA, FJ; DIAZ-RICCI, JC

Cordoba

Congreso; 52 th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2016

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 whenplants were treated simultaneously with AsES and a conidialsuspension of the pathogen Colletotrichum acutatum (isolateM11) a suppression of the AsES-inducedresponse occurred.The aim of this work was to evaluate the defense suppressionactivity in plants of strawberry of the cv. Pájaro using a purified C. acutatum M11 supernatant (SN-M11)extract by accumulationof 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‗-dichlorodihydrofluoresceindiacetate) 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.