Abstract

LOPEZ-PEREZ, Mari Carmen; PEREZ-LABRADA, Fabián; GONZALEZ-GARCIA, Yolanda  and  JUAREZ-MALDONADO, Antonio. Silicon induced positive response at biochemical and gene expression level in tomato plants inoculated with Fusarium oxysporum. Polibotánica [online]. 2024, n.57, pp.213-236.  Epub Apr 19, 2024. ISSN 1405-2768.  https://doi.org/10.18387/polibotanica.57.13.

Tomato plants infested by Fusarium oxysporum (Fol) show limitations in yield and fruit quality. The application of silicic acid could be used as an alternative to mitigate damage caused by this pathogen. In this work, the effect of silicic acid on "Rio Grande" variety tomato plants inoculated with Fol was studied. Silicic acid was applied via foliar weekly on tomato plant (ten applications). Treatments consisted of silicic acid + Fol, silicic acid, Fol and an absolute control. The incidence and severity of Fol wilt, content of antioxidant compounds (lycopene, β carotene, chlorophylls, vitamin C, reduced glutathione, phenols, flavonoids, total antioxidants and proteins), enzymatic activity (APX, CAT, GPX and SOD), PAL, salicylic and jasmonic acid, and the expression of genes involved in the synthesis of PR1, JA, GAME1, PAL5-3, ET and ABA, were determined. ASi+Fol-treated plants, compared to Fol-inoculated plants, disease incidence Fol wilt was reduced by 32% and severity by 22%, also presented an increase in chlorophyll a, b and total (49.1, 59.4 and 46.7%, respectively), as well as flavonoids (24.6%), the plants overexpressed the genes that participate in the synthesis of PR1, JA, GAME1, PAL5-3, ET and ABA at 31 dat (days after transplant), induced a reduction in reduced glutathione, antioxidant capacity by DPPH, CAT, jasmonic acid and the expression of all the genes evaluated in this work at 73 dat. The plants treated with ASi, in comparison with Fol, presented an increase in proteins, lycopene, vitamin C (30.3, 65.0, 52.7%, respectively), chlorophylls and the expression of PAL5-3 (31 dat), GAME1 and ET (73 dat). In the case Fol, a higher concentration of vitamin C, phenols, DPPH, PAL, CAT, GPX, salicylic and jasmonic acid was observed, and increase in the expression of JA, GAME1, PAL5-3, and ABA (73 dat), but it also induced a reduction in the concentration of flavonoids, chlorophylls and the expression of the six genes determined in this work at 31 dat. On the other hand, T0 plants, compared to Fol, showed an increase in proteins, lycopene, flavonoids (33.1, 62.0, 27.8%, respectively), as well as, chlorophyll, and the expression of all the genes analyzed in 31 dat, except for ET. The foliar application of silicic acid decreased the negative effects caused by Fol through the increase of antioxidant compounds and changes in the expression of genes related to the defense system in tomato plants.

Keywords : antioxidant compounds; biotic stress; defense genes expression; enzymatic activity; phytohormones.