Dec 17, 2020Field test could detect fruit-rotting diseases months before harvest
A Wenatchee-based Washington State University plant pathologist has developed an improved field test that could help apple and pear growers quickly and affordably detect pathogens that cause postharvest diseases right in their own orchards, weeks or months before symptoms appear.
Assistant Professor Achour Amiri devised a way for growers to use a low-cost, portable test, called a LAMP assay, to spot costly diseases that rot and destroy fruit.
“I was excited by the portability and user-friendliness of this test,” Amiri said. “With minimal training, orchard and warehouse staff can conduct their own detections, and then make timely decisions.”
Short for loop-mediated isothermal amplification, which describes how it amplifies DNA for detection, LAMP was developed about 20 years ago. It is often used in medicine by doctors without access to labs, recently showing promise for COVID tests. LAMP can show results in 30 minutes, and costs less than traditional lab-based tests.
LAMP tests require a primer based on the DNA of the target pathogen. Funded by the Washington State Tree Fruit Research Commission, a small team led by Amiri created a primer set for bull’s eye rot, a costly disease that mars pears and apples.
Amiri used his reagent with the LAMP test to detect the bull’s eye rot pathogen three months before harvest. The project was detailed in a paper earlier this year in the journal Plant Disease.
Now, he is developing primers for five other emerging and quarantine fruit tree pathogens found in the Pacific Northwest.
Using these primers, “all you need to do is add a small crushed chunk or volume of the sample you want to detect,” Amiri said. “That’s the beauty of this test: you don’t need to cultivate pathogens, but can simply use a suspected sample to make the diagnostic.”
In orchards, LAMP tests can yield results while trees are in bloom or while fruit is still developing, giving growers time to treat the disease.
“Early detection of disease is important for fruit growers,” Amiri said. “It helps them time their treatments to better manage disease, and to strategize when they store, ship, and market their harvest. Better disease management means increased packout and economic benefits for growers.”
– Washington State University
Assistant Professor Achour Amiri devised a way for growers to use a low-cost, portable test, called a LAMP assay, to spot costly diseases that rot and destroy fruit. Photo: Washington State University