Chemical induction of SAR in pea (Pisum sativum L.) against pea rust enhancesantifungal activity and accumulation of phenolic compounds

Abstract: In this work two different pea genotypes, the susceptible cv. Messire and the genotypePI347321 with partial resistance against the pathogen Uromyces pisi were investigated in relationto fungal development following BTH (10mm) and BABA (50mM) treatments. The effect oftreatments on β-1,3-glucanase, chitinase, phenylalanine ammonia-lyase and peroxidase activitiestogether with analysis of excreted and total soluble and wall-bound phenolic compounds werealso investigated in order to relate them to the different resistant mechanisms. Results show thatBTH and BABA systemically impair fungal development at different stages, both prior and aftermesophyll cell penetration. Fungal inhibition at early stages was associated to the production ofphenolic compounds such as scopoletin and pisatin which were found on both the excreted andthe soluble fraction following both treatments. These compounds showed a similar inhibitoryeffect when exogenously applied in vitro bioassay. Penetration and post-penetration resistancewas associated to the enhancement of PR-proteins such as β-1,3-glucanase, chitinase andperoxidase. However differences in the PR proteins induced were observed between BTH andBABA treatments.