Priming plant defenses with aspirin-like compound

Feb 14, 2014 by Jan Suszkiw
New ARS research suggests that a salicylic acid pretreatment may prevent or lessen infection of crop plants by potato purple top phytoplasma, a bacterium with no cell wall. Credit: Peggy Greb

For thousands of years, humankind has extracted salicylic acid from willow tree bark to alleviate minor pain, fever, and inflammation. Today, it's used in acne medication and wart removers, among other cosmetic products.

Now, findings by U.S. Department of Agriculture (USDA) scientists suggest salicylic acid may also offer "relief" to crop plants by priming their defenses against a microbial menace known as potato purple top phytoplasma, a bacterium that has no cell walls. Outbreaks of the bacterium in the fertile Columbia Basin region of the Pacific Northwest in 2002 and subsequent years inflicted severe potato yield and quality losses.

Carefully timed insecticide applications can deter beet leafhoppers from transmitting the phytoplasma while feeding. But once infected, the plant cannot be cured, according to Yan Zhao, a molecular biologist at the Molecular Plant Pathology Laboratory, operated in Beltsville, Md., by USDA's Agricultural Research Service (ARS).

In studies there, Zhao and his colleagues have collected evidence that pre-treating tomato plants—a relative of potato—with salicylic acid can prevent phytoplasma infections from occurring or at least diminish their severity.

For their research, published in the July 2012 Annals of Applied Biology, the team used an experimental group of potted tomato seedlings and a second group of the plants, called the control group, for comparison. The experimental group received two salicylic acid treatments—the first via a spray solution four weeks after the seedlings had been planted, and the second via a root drench two days before phytoplasma-infected scions were grafted onto the plants' stems to induce disease. The wasn't treated.

The team visually checked for disease symptoms and analyzed leaf samples for the phytoplasma's unique DNA fingerprint, which turned up in 94 percent of samples from untreated plants and 47 percent of treated ones. Significantly, the remaining 53 percent of treated were symptom- and pathogen-free 40 days after exposure to the infected scions.

Researchers credit with triggering systemic acquired resistance, a kind of general readiness state that primes plant defenses against pending microbial or insect attack.

Explore further: Researchers identify amino acid change that allows pathogens to jump from one plant to another

More information: Read more about this research in the February 2014 issue of Agricultural Research magazine.

add to favorites email to friend print save as pdf

Related Stories

Microbes help beetles defeat plant defenses

Sep 09, 2013

Some symbiotic bacteria living inside Colorado potato beetles can trick plants into reacting to a microbial attack rather than that of a chewing herbivore, according to a team of Penn State researchers who ...

'Fountain of youth' for leaves discovered

Aug 23, 2013

What plant scientists call senescence, consumers experience as wilted produce and overripe fruit. A team led by Cornell horticulture professor Su-Sheng Gan has identified an enzymatic fountain of youth that ...

Recommended for you

The origin of the language of life

Dec 19, 2014

The genetic code is the universal language of life. It describes how information is encoded in the genetic material and is the same for all organisms from simple bacteria to animals to humans. However, the ...

Quest to unravel mysteries of our gene network

Dec 18, 2014

There are roughly 27,000 genes in the human body, all but a relative few of them connected through an intricate and complex network that plays a dominant role in shaping our physiological structure and functions.

EU court clears stem cell patenting

Dec 18, 2014

A human egg used to produce stem cells but unable to develop into a viable embryo can be patented, the European Court of Justice ruled on Thursday.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.