Preservation of Fusarium oxysporum Endophytes and Pathogenic of Vanilla.

The preservation of phytopathogenic fungi is essential for maintaining biological collections that support research and disease management strategies. Among the most important diseases affecting vanilla cultivation is root and stem rot caused by Fusarium oxysporum f. sp. vanillae. Since 2010, a collection of pathogenic and endophytic F. oxysporum strains associated with Vanilla planifolia and related Vanilla spp. has been maintained at the Universidad Veracruzana, Mexico. This chapter describes methodologies for strain isolation, morphological characterization, pathogenicity assessment, and long-term preservation. Protocols employing selective culture media, pathogenicity assays, and two preservation strategies-vegetative mycelium storage in minimal medium and chlamydospore conservation under low temperaturesṣ-are presented. These approaches ensure the maintenance of fungal viability, genetic stability, and pathogenic capacity, providing a reliable framework for phytopathological and molecular studies involving vanilla-associated Fusarium strains.