Characterization of functionalized bentonite as nanocarrier of salicylic acid with protective action against Pseudomonas syringae in tomato plants

MANSILLA, A.Y.; SALCEDO, M.F.; COLMAN, S.L.; CHEVALIER, M.T.; LANFRANCONI, M.; ALVAREZ, V. A.; CASALONGUÉ, C.A.

EUROPEAN JOURNAL OF PLANT PATHOLOGY

SPRINGER

Lugar: Berlin; Año: 2020

0929-1873

Salicylic acid (SA) is a phytohormone with a central role in plant protection against various types of stresses. Exogenous application of SA in plants often requires a fine adjustment of the pH in the applied solution as well as frequent foliar sprays with rigorous handling of its doses. This work investigates the preparation and characterization of nanocomposites composed of the bentonite clays (Bent) and SA as biocative to produce an efficient and stable hormonal formulation to be used in agriculture. Bent-SA was obtained via cationic exchange reactions of natural Bent with an aqueous solution of SA. The physicochemical properties of Bent-SA were studied in terms of Fourier Transform Infrared Spectroscopy (FTIR), X Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA). SA was intercalated in a 3.65% w/w interacting by electrostatic forces between Bent layers. The SA protective activity was investigated in Pseudomonas syringae pv. tomato DC3000 (Pto)-infected tomato plants (Solanum lycopersicum). The expression levels of pathogenesis-related proteins (PRs) were measured by real time quantitative RT-PCR. The genes PR1 and PR5 were up-regulated 2.2- and 1.23-fold, respectively, in 24 h-treated Bent-SA plants. Furthermore, PR3 protein level increased locally and systemically by Bent-SA treatment in plant tissues. The plant disease incidence was significantly reduced in Bent-SA pretreated seedlings. Analyses of DR5:GUS transgenic reporter tomato lines showed that Bent-SA effectiveness was preserved after vehiculization. Then it was concluded that Bent-SA can provide an environmentally friendlier strategy to control tomato plants against Pto bacterial infection.