Biphasic sctivation of defense response in strawberry plants treated with elicitor protein AsES

PERATO, SILVIA MARISA; HAEL CONRAD, VERÓNICA; DÍAZ RICCI, JUAN C.

Rosario, Santa Fe.

Congreso; SAIB 51º Annual Meeting; 2014

Argentine Society for Biochemistry and Molecular Biology

AsES is a subtilisin-like protease isolated from the avirulent fungus Acremonium strictum which exhibits defense-eliciting activity against virulent Colletotrichum actatum M11 in strawberry. In this work we focus on elucidating the effect of AsES on some biochemical and molecular markers in strawberry plants at different times. We studied production of reactive oxygen species (ROS) and the expression of genes related to ROS detoxification (FaCAT), salycilic acid (FaPR1) and ethylene (FaACS, FaACO2, FaETR1) defense pathways at 2, 12, 24, 48, 72, 92, 120 hours post treatment (hpt) with AsES. Our results showed a strong, biphasic, oxidative burst (accumulation of H2O2 and O2-) with peaks at 12 and 120 hpt and downregulation of FaCAT gen at 2, 48 and 120 hpt. A biphasic behavior was also observed in the expression of FaPR1, with a peak at 72 hpt, and a much greater one at 120 hpt. In contrast, expression of the gene FaETR1 (an ET receptor) was downregulated 120 hpt suggesting a negative cross-talk between the two pathways. Furthermore, the genes FaACS and FaACO2 (ET synthesis enzymes) were downregulated up to 48 hs and then expression level increases being higher the FaACO2, indicating a late activation of ET pathway. These results agree with previous observations of our group that elicitation was higher when inoculation with M11 was carried out 120 hpt with AsES.