Pathogenicity and Phylogenetic Placement of Fusarium proliferatum Causing Rot of Garlic Bulbs in Storage

Abstract

Fusarium proliferatum is an important soil- and storage-borne fungal pathogen responsible for post-harvest losses in a wide range of crops, including garlic. The present study was conducted to investigate the pathogenicity and phylogenetic placement of F. proliferatum associated with bulb rot of Garlic under storage conditions. Diseased garlic bulbs exhibiting symptoms of soft rot, discoloration, shriveling, and internal tissue decay were collected from storage facilities. The pathogen was isolated on potato dextrose agar and identified based on morphological characteristics such as colony pigmentation, microconidia and macroconidia morphology, and chlamydospore formation. Pathogenicity tests were performed by inoculating healthy garlic bulbs under controlled storage conditions, which resulted in the development of typical rot symptoms, thereby confirming the virulence of the isolate. The pathogen was re-isolated from infected tissues, fulfilling Koch’s postulates. For molecular characterization, genomic DNA was extracted and amplified using ITS region primers, followed by sequencing and phylogenetic analysis. Sequence comparison revealed high similarity with reference F. proliferatum isolates available in public databases. Phylogenetic reconstruction placed the isolate within a distinct clade of Fusarium species complex, confirming its taxonomic identity and evolutionary relationships. The study highlights the aggressive nature of F. proliferatum under storage environments and its potential to cause significant post-harvest losses in garlic. The integration of pathogenicity assays with molecular phylogenetics provides a reliable approach for accurate identification and understanding of the epidemiology of storage rot pathogens. These findings emphasize the need for improved storage hygiene, disease monitoring, and integrated post-harvest management strategies to minimize losses and maintain garlic quality during storage.