Histopathological and histochemical alterations resulting from Phytophthora infestans infection in the potato plant Solanum tuberosum (Solanaceae)

Research on the histopathological and histochemical responses of the Phytophthora infestans/Solanum tuberosum pathosystem is limited in the scientific literature. The morpho-anatomy of the leaves and stems aligns with typical descriptions of most eudicot angiosperms. The cuticular patterns observed were not previously documented in specialized literature, and notable ultrastructural differences were found that varied by the genotype analyzed. The leaves are distinctly hypostomatic. Histopathologically, both the biotrophic and necrotrophic phases of the pathogen were observed, primarily affecting the primary tissues of the leaves and stems. All the infected genotypes exhibited an increase in the synthesis and accumulation of lignin, pectins, and polyphenols. In contrast, only the ESTRELLA and BETINA genotypes demonstrated synthesis and deposition of callose in response to the pathogen during sporulation. The histopathological and histochemical responses observed in this pathosystem are similar to those described in previous studies, even in other pathosystems. The pronounced differences in callose synthesis and accumulation are particularly noteworthy and may indicate a potential late resistance mechanism to the pathogen, which could be valuable for breeding programs aimed at developing varieties with enhanced resistance.