Extraction of Plant DNA by Microneedle Patch for Rapid Detection of Plant Diseases.

In-field molecular diagnosis of plant diseases via nucleic acid amplification (NAA) is currently limited by cumbersome protocols for extracting and isolating pathogenic DNA from plant tissues. To address this challenge, a rapid plant DNA extraction method has been developed using a disposable polymeric microneedle (MN) patch. By applying MN patches on plant leaves, amplification-assay-ready DNA can be extracted within a minute from different plant species. MN-extracted DNA has been used for direct polymerase chain reaction (PCR) amplification of plant plastid DNA without purification. Furthermore, using this patch device, extraction of plant pathogen DNA (Phytophthora infestans) from both laboratory-inoculated and field-infected leaf samples was performed for detection of late blight disease in tomato. MN extraction achieved 100% detection rate of late blight infections for samples after 3 days of inoculation when compared to the conventional cetyltrimethylammonium bromide (CTAB)-based DNA extraction method as a gold standard, and 100% detection rate for all blind field samples tested. This simple, cell lysis-free, and purification-free DNA extraction method could be a transformative approach to facilitate rapid sample preparation for molecular diagnosis of various plant diseases directly in the field.