Larrea nitida Cav. nanodispersions promote extra resistance against pathogenicity in tomato plants

ROCHA, F.; CALUMBY, R.J. N.; SALOMÓN, A.; SVETAZ, L.; SORTINO, M.; CAMPOS-BERMUDEZ, V. A.; RIUS, S. P.

Congreso; 32 Congresso Brasileiro Microbiologia; 2023

Larrea nitida Cav. is a plant that possesses antimicrobial compounds commonly found in South America, more specifically in Argentina and Chile. However, the organic extracts derived from the plant have a highly hydrophobic nature, which makes their application challenging without the use of organic solvents . In this context, the solid dispersion technique was used to produce water soluble nanoparticles containing L. nitida extract by using a mixture betwee n polietilenoglicol PEG and zinc acetate as wall materials ( PZLE). Ultraviolet Visible Spectroscopy (UV Vis) and Fourier Transform Infrared Spectroscopy (FTIR) show that the complexation between the compounds was successfully done, and the results obtain ed by the Transmission Electronic Microscopy (TEM) confirm that the particles were produced on a nanometric size. In order to assess the effects of the nanoparticles in promoting an extra resistance against pathogenicity, 2 weeks old tomato plants were tre ated with a solution containing L. nitida nanodispersions (33 and 100 mg.L 1 ) and surfactant (Silwet 0.05%) thrice a week for 1 week. Two weeks after the treatment, leaves (3 and 4) of the plant were detached and infected with Fusarium oxysporum (10 7 conidia) and Pseudomonas syringae pv. tomato (OD 600 = The infected leaves were placed in glass recipients at room temperature, in the absence of light and with controlled humidity. T he progression of the infection w as evaluated daily. After 1 week, the sof tware ImageJ was used to calculate the apparent damage on the leaves, and it was possible to observe that the plants treated with th e nanodispersions had significantly fewer symptoms when compared to the control leaves , treated only with water and Silwet 0.05%. The protective effect of the nanodispersions can be due to the presence of both zinc compounds and the presence of antimicrobial and antioxidant compounds in the nanoparticles.