UNDARIA PINNATIFIDA AQUEOUS EXTRACT AS A RESISTANCE INDUCER AGAINST P. INFESTANS

OLIVIERI FP; MACHINANDIARENA MF; LOBATO MC; BECHERUCCI ME; SISTI V; ARMANI T; FELDMAN ML

Congreso; LVII SAIB Meeting- XVI SAMIGE Meeting; 2021

SAIB- SAMIGE

Sustainable agricultural practices increasingly demand novel environmentally friendly compounds which induce plant immunity against pathogens. Stimulating plant immunity using seaweed extracts is a highly viable strategy, as these formulations contain many bio-elicitors which can significantly boost natural plant immunity. Certain bioactive elicitors present in a multitude of extracts of seaweeds may activate plant´s defense responses.Undaria pinnatifida is an invasive macroalgae in Argentinean coast and its use as a biostimulant has begun to be studied. Therefore, the aim of the present work is to evaluate the effect of algae extracts (EA) on potato defense responses. Our preliminary results showed that Undaria pinnatifida aqueous extracts (EA) protected potato plants against Phytophthora infestans infection (Pi). We analyzed the expression of genes that might be involved in this process, as PR1 and IPII genes (Salicylic Acid and Jasmonic acid pathways markers respectively). We found that PR1 increased its expression by infection with P. infestans, but increased much more in plants treated with EA, 5 days after Pi inoculation. However, IPII expression, showed an increment only when EA was applied. Additionally, the expression of two genes involved in induced resistance was analyzed: POPA (a guaiacol peroxidase) and SNRKI (a stress marker). Both genes increased their expression after Pi inoculation, but POPA increased to a higher extent after EA+Pi treatment in accordance with total peroxidase activity visualized in a zymogram. Other defense response, as changes in polyamine content, was also analyzed. Preliminary results have shown that Spermine is induced after EA treatment and was higher in EA+Pi. We have previously shown that potassium phosphites (KPhi) induced the above responses in disease and UV-B stress tolerance, therefore, we started analyzing if the combination of both compounds enhances the beneficial effects already described for phosphites.The possibility of taking advantage of a local resource such as the invasive algae Undaria pinnatifida, as an inducer of the defense responses against P. infestans infection on potato plants, or its possible role to increase the known beneficial effects of the phosphite compounds, would allow the use of a natural resource available in the region, and eventually generate a strategy to improve crops without environmental risk. Moreover, the bioprospection of algae may contribute reducing its detrimental effects on coastal marine ecosystems.