Nav: Home

New microneedle technique speeds plant disease detection

June 10, 2019

Researchers have developed a new technique that uses microneedle patches to collect DNA from plant tissues in one minute, rather than the hours needed for conventional techniques. DNA extraction is the first step in identifying plant diseases, and the new method holds promise for the development of on-site plant disease detection tools.

"When farmers detect a possible plant disease in the field, such as potato late blight, they want to know what it is right away; rapid detection can be important for addressing plant diseases that spread quickly," says Qingshan Wei, an assistant professor of chemical and biomolecular engineering at North Carolina State University and co-corresponding author of a paper on the work.

"One of the obstacles to rapid detection is the amount of time it takes to extract DNA from a plant sample, and our technique provides a fast, simple solution to that problem," Wei says.

"Some plant diseases have similar leaf symptoms, such as late blight caused by the famed Irish famine pathogen Phytophthora infestans, and Phytophthora blight caused by a sister species P. nicotianae," says Jean Ristaino, William Neal Reynolds Distinguished Professor of Plant Pathology at NC State and co-corresponding author of the paper. "The gold standard for disease identification is a molecular assay. Our new technique is important because you can't run an amplification or genotyping assay on strains of P. infestans, or any other plant disease, until you've extracted DNA from the sample."

Typically, DNA is extracted from a plant sample using a method called CTAB extraction, which has to be done in a lab, requires a lot of equipment, and takes at least 3 to 4 hours. CTAB extraction is a multi-step process involving everything from tissue grinding to organic solvents and centrifuges.

By contrast, the new DNA extraction technique involves only a microneedle patch and an aqueous buffer solution. The patch is about the size of a postage stamp and is made of an inexpensive polymer. The surface on one side of the patch is made up of hundreds of needles that are only 0.8 millimeters long.

A farmer or researcher can apply the microneedle patch to a plant they suspect is diseased, hold the patch in place for a few seconds, then peel it off. The patch is then rinsed with the buffer solution, washing genetic material off of the microneedles and into a sterile container. The entire process takes about a minute.

"It is exciting to see the new application of microneedle patch technology in agriculture and plant science," says Zhen Gu, a professor of bioengineering at the University of California, Los Angeles and co-corresponding author of the paper, who developed several microneedle-based drug delivery systems for human health.

"In experimental testing, we found that the microneedle technique does result in slightly higher levels of impurities in the sample, as compared to CTAB," Wei says. "However, the microneedle technique's purity levels were comparable to other, validated laboratory methods of DNA extraction. Most importantly, we found that the slight difference in purity levels between the microneedle and CTAB samples did not interfere with the ability to accurately test the samples by a PCR or LAMP assay."

"The fact that microneedles extract a smaller sampling volume seems not to be an issue," says Rajesh Paul, a Ph.D. student at NC State and first author of the paper. "The microneedle technique successfully extracted pathogen DNA from all field-collected infected tomato leaves in a recent blind test."

"DNA extraction has been a significant hurdle to the development of on-site testing tools," Wei says. "We are now moving forward with the goal of creating an integrated, low-cost, field-portable device that can perform every step of the process from taking the sample to identifying the pathogen and reporting the results of an assay."

The paper, "Extraction of Plant DNA by Microneedle Patch for Rapid Detection of Plant Diseases," is published in the journal ACS Nano. The paper was co-authored by Amanda Saville, lab manager in Ristaino's lab; Jeana Hansel, a graduate student at NC State; Carmin Ball and Alyssa Williams, undergraduates at NC State; Yanqi Ye, a former graduate student in the Joint Biomedical Engineering Department at NC State and the University of North Carolina, Chapel Hill; Xinyuan Chang, an undergraduate at Tianjin University who worked as a visiting researcher at NC State; and Guojun Chen, postdoctoral researcher at UCLA.
-end-
The work was done with support from the NC State Chancellor's Faculty Excellence Program on Emerging Plant Disease and Global Food Security, the Kenan Institute for Engineering, Technology & Science at NC State, and the USDA Integrated Pest Information Platform for Extension and Education, under grant number 2015-0097.

North Carolina State University

Related Dna Articles:

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.
Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.
DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.
A new spin on DNA
For decades, researchers have chased ways to study biological machines.
From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.
Self-healing DNA nanostructures
DNA assembled into nanostructures such as tubes and origami-inspired shapes could someday find applications ranging from DNA computers to nanomedicine.
DNA design that anyone can do
Researchers at MIT and Arizona State University have designed a computer program that allows users to translate any free-form drawing into a two-dimensional, nanoscale structure made of DNA.
DNA find
A Queensland University of Technology-led collaboration with University of Adelaide reveals that Australia's pint-sized banded hare-wallaby is the closest living relative of the giant short-faced kangaroos which roamed the continent for millions of years, but died out about 40,000 years ago.
DNA structure impacts rate and accuracy of DNA synthesis
DNA sequences with the potential to form unusual conformations, which are frequently associated with cancer and neurological diseases, can in fact slow down or speed up the DNA synthesis process and cause more or fewer sequencing errors.
Changes in mitochondrial DNA control how nuclear DNA mutations are expressed in cardiomyopathy
Differences in the DNA within the mitochondria, the energy-producing structures within cells, can determine the severity and progression of heart disease caused by a nuclear DNA mutation.
More DNA News and DNA Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.