Carboidratos do fungo Pycnoporus sanguineus para proteção de tomateiro contra Meloidogyne incognita

Abstract

Tomato (Solanum lycopersicum) is affected by several major pathogens, among which rootknot nematodes such as Meloidogyne incognita are particularly significant. Due to the difficulty in managing this pest—mainly because of the limited availability of resistant genotypes and the high toxicity of chemical nematicides—it is essential to seek new control strategies, especially those that meet the global demand for environmentally safe methods. Pycnoporus sanguineus is a basidiomycete fungus capable of producing elicitor molecules with potential to induce resistance in tomato plants.The objective of this study was to use structural carbohydrates (SC) extracted from the basidiocarp of P. sanguineus for the control of M. incognita in tomato plants. Concentrations of 0, 100, 200, 400, and 500 mg L⁻¹ of SC were used in in vitro assays to evaluate nematicidal and/or nematostatic activity, and in in vivo assays to assess pathogen control in tomato plants. In the in vivo experiments, three application methods were tested: root immersion, foliar spraying, and a combination of both, all applied three days before pathogen inoculation.The following parameters were evaluated: number of galls and egg masses, egg viability, number of eggs and second-stage juveniles (J2) in both soil and roots, and the reproduction factor. A slight in vitro nematicidal effect was observed at the concentration of 500 mg L⁻¹, resulting in an 18% increase in J2 mortality. In in vivo assays with different concentrations, a reduction of 50% in gall number, 67% in egg masses, 64% in nematodes in the soil, 76% in egg viability, and 32% in the reproduction factor was observed. The most effective application method was the combination of foliar spraying and root immersion, which led to a 70% and 74% reduction of nematodes in roots and soil, respectively, a 62% reduction in egg viability, and a 68% decrease in the reproduction factor. These results indicate the potential of structural carbohydrates from P. sanguineus for the control of M. incognita in tomato plants.