PR-protein activities in table beet against Cercospora beticola after spraying chitosan or acibenzolar-S-methyl

Abstract

Cercospora leaf spot (Cercospora beticola) is the most important disease of table beet in the world. In this study, the preventive application of chitosan or acibenzolar-S-methyl (ASM) to control the disease was evaluated, and the involvement of pathogenesis-related proteins in the plant-pathogen interaction was verified. Beet plants cultivar Early Wonder were sprayed with distilled water, HCl 0.05 N, chitosan at 2 mg/mL or 4 mg/mL and ASM at 25 mg/L, and 24 h or three days later, inoculated with the pathogen. Leaf samples were collected at different times after spraying and enzymatic activities were quantified spectrophotometrically. It was observed that chitosan and ASM reduced disease severity in table beet leaves by 76% and 68%, respectively, on the average of two experiments, and ASM promoted the accumulation of peroxidases and β-1,3 glucanases in beet leaves. Thus, both inducers reduce cercospora leaf spot in table beet, and the effect of ASM is associated with the activation of PR-proteins, whereas chitosan act by a still unknown mechanism.

Phosphites for the control of anthracnose in common bean

“…Borsato et al (2010) observed an increase of 65% in the peroxidase activity 48 hours after inoculation of Uromyces appendiculatus on the susceptible cultivar IPR Juriti of common bean, when compared with the resistant cultivar BR IPA 11 (Brígida). Felipini & Di Piero (2013) verified that ASM induced resistance by promoting the accumulation of peroxidases and β-1,3 glucanases in beet (Beta vulgaris L.) leaves. Regarding lignin content, no differences were verified between the treatments, in alignment with the results of Daniel & Guest (2006).…”

Resistance of cactus pear (Opuntia ficus-indica) againstPseudocercospora opuntiaethroughβ‑1,3‑glucanase activity and polyphenolic compounds in cladodes

“…Higher glucanase activity was registered in cladodes of the R genotype compared with S, 10.3 and 4.95, respectively (Table 2). Previous studies have shown that the production of glucanases has been linked to the selection of resistant plants to Pseucocersospora and Cercospora (Sundaresha et al, 2010;Felipini and Di Piero, 2013;Qiao et al, 2014).…”

“…Arachis hypogaea plants were transformed with a gene for β-1,3-glucanase, coding for a 38-aminoacid protein (38.8 kDa), and showed resistance to Cercospora personata (Sundaresha et al, 2010;Qiao et al, 2014). In Beta vulgaris inoculated with chitosan in order to induce defense mechanisms, β-1,3-glucanase accumulated and, with it, the damage caused by Cercospora beticola diminished (Felipini and Di Piero, 2013).…”