Ultrasensitive isothermal detection of a plant pathogen by using a gold nanoparticle-enhanced microcantilever sensor

Sensitive and rapid detection of plant pathogens, particularly for on-site diagnosis during custom inspections, is essential to prevent and control the spread of these pathogens. To address the need, a combined assay for detecting plant pathogens was developed by using gold nanoparticle-enhanced dynamic microcantilever (MCL) biosensing and isothermal recombinase polymerase amplification (RPA). In this study, we used Leptosphaeria maculans (L. maculans), an aggressive fungus responsible for major losses in oilseed rape yield worldwide, as the target pathogen to demonstrate the merits of the combined RPA and MCL strategy (named as the RPA-MCL assay). The results indicated that the sensitivity of the RPA-MCL assay is higher than that of the fluorescence RPA assay, with the detection limit of only one copy of L. maculans DNA. In the practical assay, the newly developed RPA-MCL method was found to detect 57 ppm L. maculans genomic DNA in the oilseed rape seeds genomic DNA sample. Considering the high sensitivity and specificity of this strategy, we envision that the proposed RPA-MCL assay could have wide applications in nucleic acid diagnostics for on-site plant pathogen detection and species identification.

Automated summary

A combined assay utilizing gold nanoparticle-enhanced dynamic microcantilever biosensing and isothermal recombinase polymerase amplification was developed for detecting plant pathogens. The sensitivity of the RPA-MCL assay was demonstrated to be higher than that of the fluorescence RPA assay, with the ability to detect as low as one copy of the target pathogen DNA. This newly developed method shows potential for wide applications in on-site plant pathogen detection and species identification.