Identification and molecular characterization of eggplant (Solanum melongena L.) germplasm for resistance to Fusarium spp.

Eggplant wilt, caused by Fusarium oxysporum and Neocosmospora solani, is among the most devastating soil-borne diseases, posing a major challenge to sustainable cultivation. The combined threat from these pathogens necessitates the identification of genotypes resistant to multiple Fusarium isolates and a deeper understanding of the defence mechanisms underlying durable resistance. While resistance to F. oxysporum has been reported in certain cultivated and wild accessions, no reliable source of resistance to N. solani has yet been identified and the molecular basis of wilt resistance remains poorly understood. In this study, seventeen eggplant germplasm lines, including released cultivars and two wild Solanum relatives, were evaluated against a highly virulent F. oxysporum isolate (BRFO-VRF-8) under both pot and field sick-plot conditions. Among the tested lines, DBR-160-2-3-1-3 consistently exhibited a significantly lower percent disease index (PDI), vigorous growth, and better physiological performance than susceptible checks. Subsequent pathogenicity assays revealed that its resistance extended to N. solani and combined Fo + Ns inoculations, indicating a broad-spectrum and stable resistance response. Molecular characterization using CAPS marker and R-gene analysis indicated that this resistance operates independently of previously known mono- or polygenic loci, suggesting a novel genetic basis. Quantitative RT-PCR profiling showed a strong upregulation of six key defence-related genes endochitinase ( vir1 ), PR-1, PR-2, PR-5, PR-7 , and phenylalanine ammonia-lyase (PAL) implying their coordinated role in systemic defence activation and cell wall reinforcement against vascular wilt pathogens. Further field validation under endemic conditions confirmed that DBR-160-2-3-1-3 maintained a consistently low PDI and produced significantly higher fruit yield than the susceptible check, Pusa Hara Baingan 1. Overall, the integration of phenotypic, pathogenic, and molecular evidence establishes DBR-160-2-3-1-3 as a novel and stable source of resistance to both F. oxysporum and N. solani . Its broad-spectrum resistance and superior field performance make it a promising donor for introgression into elite breeding lines, facilitating the development of durable, wilt-resistant eggplant cultivars for sustainable production. • DBR-160-2-3-1-3 eggplant resisted Fusarium oxysporum and Neocosmospora solani , resulting in lower wilt and higher yield. • Marker analysis using CAPS and R-gene profiling confirmed that the observed resistance operates independently of known loci such as Rfo-sa1. • qRT-PCR analysis showed upregulation of defence genes, indicating a distinct molecular mechanism underlying the resistance.