Article | Challenges in LAMP-based detection of Fusarium spp. responsible for dry rot in garlic

Guilbaud, C., Troulet, C., Lacroix, C., Muller, E., Leyronas, C., (2026) Challenges in LAMP-based detection of Fusarium spp. responsible for dry rot in garlic. Physiological and Molecular Plant Pathology, 145. https://doi.org/10.1016/j.pmpp.2026.103355

Résumé : Fusarium dry rot disease (FDR) is an emerging disease worldwide mainly caused by Fusarium proliferatum (Fp) but also by F. oxysporum (Fox). It renders garlic cloves unfit for consumption. Fp and Fox are often present in cloves as an endophyte making it difficult to evaluate garlic health status and to forecast symptoms appearance. To date, there is no simple, rapid test for the detection of Fp and Fox that can be used in the field and help growers to improve garlic production, especially through the management of asymptomatic cloves. This study assesses the challenge of detecting Fp (the main causal agent of FDR) directly on garlic cloves, with Loop mediated isothermal technology (LAMP), and results visualized using turbidity or Phenol-red. We used primers originally designed for Fp strains of maize, tested them on garlic tissues with DNA and mycelium, with and without a prior DNA isolation step. The LAMP assay combined with a prior DNA isolation step using FTA Card, produced the best results. These results obtained from the previously inoculated garlic were consistent with the observed symptoms on garlic and mycelium growth on agar. Sensitivity was variable among strains, ranging from 1 to 50 μg μL⁻¹ per LAMP for mycelium. The LAMP assay was not entirely specific to Fp as several Fox strains were also amplified. Overall, this study shows that a simple FTA Card DNA extraction step is useful for the field detection of Fusarium spp. strains responsible of FDR on garlic. Methods to improve the specificity of the developed LAMP assay to detect only Fp strains are discussed.