Isoenzymatic Profiles during Early Stages of Haustoriogenesis within the Genus Cuscuta Are Taxonomically Dependent

Abstract

Haustorium formation is the key developmental event enabling parasitism in the genus Cuscuta, yet comparative data on the enzymatic mechanisms underlying haustoriogenesis across taxonomically distinct species remain scarce. In this study, we investigated whether isoenzymatic profiles associated with early haustorium formation are taxonomically dependent within Cuscuta. Nine species representing three major subgenera – Grammica, Cuscuta, and Monogynella – were analyzed. Haustoria were induced using artificial hosts, and soluble protein extracts from the haustorial region were subjected to zymographic analysis of peroxidases, proteases, and cellulases. Peroxidases exhibited the highest diversity, with 16 distinct isoforms detected and clear interspecific and intersubgeneric differences. Protease activity was represented by a limited number of isoforms with species-specific electrophoretic mobility, whereas cellulase activity was detected only in two species. Cluster analysis based on combined peroxidase and protease isoenzyme profiles produced a dendrogram that largely reflected established taxonomic relationships, clearly separating the three subgenera. These findings demonstrate that isoenzymatic patterns during haustoriogenesis are not random but are evolutionarily linked to major lineages within Cuscuta. The results support the hypothesis that taxonomically related dodder species employ similar enzymatic strategies during host invasion, providing functional biochemical support for existing phylogenetic frameworks.