(100g) Minimally Invasive Extraction of Plant DNA Via a Polymeric Microneedle Patch for on-Site Detection of Plant Pathogens

Molecular diagnoses play an essential role for identification of plant pathogens and global crop protection. However, extraction of DNA from plant cells is challenging due to the presence of surrounding polysaccharide cell walls. As a result, isolation of high-quality plant DNA is mainly confined to well-equipped laboratories, and sample preparation becomes one of the major hurdles to perform molecular diagnostic assays of plant pathogens in the field. To expedite sample preparation and pathogen detection on site, a simple and rapid DNA extraction method has been developed using a polymer microneedle (MN) patch to isolate genomic or pathogenic DNA from plant leaves. This minimally invasive DNA extraction method isolated amplification assay ready DNA from several plant species within a minute. Furthermore, MN extraction of pathogenic DNA was tested and compared to conventional cetyltrimethylammonium bromide (CTAB) extraction by isolating Phytophthora infestans DNA from infected tomato leaves for late blight disease detection. For laboratory-inoculated samples, the MN extraction matched the performance of the CTAB method for samples after 3 days of inoculation. For field-collected samples, MN patches successfully isolated P infestans DNA from all leaf samples. These MN patches could be used to diagnose other plant pathogens from various plant species, and thus have great potential to become a general sample preparation technique for on-site molecular diagnosis of plant diseases.