(Beyond Pesticides, March 8, 2012) Researchers at Montana State University-Bozeman (MSU) have discovered a bacterium that could control a variety of plant diseases caused by funghi, bacteria and viruses, and are working with Certis USA, a global biological pesticide company, to develop and commercialize it by early 2013. The product will be based on Bacillus mycoides isolate J, (BmJ), which itself is a naturally occurring, nonpathogenic bacterium that triggers a plant’s immune response to pathogenic funghi, bacteria and viruses resulting in systemic acquired resistance to diseases. BmJ belongs to the Bacillus cereus complex, which also includes Bacillus Thuringiensis (Bt), a soil bacterium that is used as biological pesticide by organic farmers, but also widely incorporated into some genetically engineered crops.
MSU scientist Barry Jacobsen, Ph.D. first discovered the bacterium in 1994 when a field of sugar beet crops in Sidney, MT had been devastated and nearly wiped out due to the Cercospora leaf spot. Area farmers were spending millions of dollars on aerial applications of fungicides to fight the disease, but were losing the battle due to resistance. Dr. Jacobsen and his team of researchers looked to the few surviving plants to find out what enabled them to ward off the fungal disease.
The researchers isolated over 300 bacteria found on the healthy leaves, and found that one- Bacillus mycoides isolate J- had the ability to fight the Cercospora leaf spot. It works by turning on one particular gene, the NPR1 gene, which is found in most plants and most food crops except for peanuts. When this gene is turned on, it triggers the plant’s immune response, setting in motion a whole range of defenses for the plant.
“Within five minutes of that bacillus spore being on the plant leaf, the plant knows it’s there and it starts its defense reactions,” said Dr. Jacobsen. “It reacts by producing hydrogen peroxide and some other things and this thickens cell walls and makes it more difficult for a pathogen to infect. Within a day it starts to produce enzymes that attack fungi and bacteria. And it’s very effective on viruses as well, but so far we don’t understand how that happens.”
Researchers aren’t certain how exactly the immune response is triggered. However, BmJ need only be sprinkled on any location of the plant for the NPR1 gene to activate throughout the entire plant.
Dr. Jacobson believes that BmJ should provide stable and predictable protection to farmers when it is used in an integrated approach with other disease-fighting measures. Ultimately, he says it could reduce the use of toxic fungicides and pesticides. Because it is naturally occurring and has not been genetically modified, Dr. Jacobsen also says, “it should be labeled as available for organic gardeners.”
MSU has patented all methods for inducing SAR in plants through BmJ-based control agents; related patents are pending. The technology has been under development by MSU and Montana BioAgriculture, and the collaboration has proven the efficacy of BmJ against Cercospora leaf spot in sugar beets, white mold and early blight in potatoes, and several other crop diseases. Certis USA plans to commercialize this technology worldwide in an expanded range of crops and diseases.