Fungal-specific lectin FGB1 based LAMP assay for specific detection of Fusarium oxysporum f. sp. ciceris causing Fusarium wilt in chickpea

F. oxysporum f. sp. ciceris is a soil borne species complex having both virulent as well as non-pathogenic strains. In order to accurately diagnose virulent strains, appropriate genic regions must be targeted. In this study, an FGB1 (fungal-specific beta-glucan-binding lectin) gene-based PCR, qPCR and LAMP assays were developed and validated among closely related species of F. oxysporum. Conventional PCR showed amplification of a F. oxysporum f. sp. ciceris specific band. qPCR assay could detect 0.6 fg/ mu L of pathogenic DNA with no amplification in no template control. The LAMP assay was highly specific and could detect F. oxysporum f. sp. ciceris among eleven other similar fungal outgroups. The assay could detect 3.21 fg/mu L of pathogenic DNA within 15 minutes having higher sensitivity as compared to conventional PCR assay. The LAMP assay was further validated on plant and soil samples collected from chickpea fields at two different locations and time intervals. The results obtained clearly indicated that with the help of LAMP diagnostic assay, early onset of the disease could be predicted which might help in the timely management of Fusarium wilt.