Molecular Detection and Characterization of Oomycete Pathogens Associated with Root Diseases of Saffron Corms

Abstract

Molecular detection and characterization of oomycete pathogens associated with root diseases of saffron (Crocus sativus L.) corms were conducted to identify causal agents and assess their genetic diversity. Diseased corms exhibiting soft rot, browning, and reduced sprouting were collected from saffron-growing fields, and pathogen isolation was performed using selective media. Morphological identification suggested the presence of Pythium and Phytophthora species, which was further confirmed through molecular assays. PCR amplification targeting ITS rDNA and species-specific genomic regions enabled accurate detection and differentiation of oomycete pathogens. Sequencing and phylogenetic analysis revealed the occurrence of multiple genetically distinct lineages associated with saffron root and corm rot, indicating a complex pathogen community. Among the detected taxa, Pythium spp. were predominant, while Phytophthora spp. were also present in certain samples, contributing to disease severity. Variation in virulence among isolates was observed under pathogenicity assays, with highly aggressive strains causing rapid corm decay and poor plant establishment. The study highlights the role of soil-borne oomycetes in saffron decline and emphasizes the importance of early molecular diagnostics for disease management. These findings provide a foundation for developing targeted control strategies, including improved corm health management, soil sanitation, and resistant cultivar selection to mitigate losses caused by oomycete infections in saffron cultivation systems.