Beneficial bacteria that could promote crop growth and reduce dependence on commercial fertilizers have been identified by an Agriculture and Agri-Food Canada (AAFC) research scientist.

The bacterium works by enhancing the root size of crops, thereby increasing uptake and fixation of important soil nutrients, like nitrogen, says Dr. Ze-Chun Yuan, a plant protection scientist at AAFC’s London Research and Development Centre who made the discovery.

Larger roots enhance growth because “better nutrient uptake can help plant growth by allowing nutrients to enter the plant’s shoots,” Dr. Yuan says. "My lab identified very useful bacteria with beneficial traits, such as Paenibacillus polymyxa CR1, which fixes nitrogen and produces naturally occurring plant hormones that can help with plant growth."

So far, he has identified three bacteria with potential beneficial applications for plants. One bacterium, Paenibacillus polymyxa CR1, has been found to fix nitrogen and produce naturally occurring growth hormones which enhance plant growth.  Additionally, the beneficial bacteria produce chemicals, both internally and externally, which could help the plant increase its resistance to diseases and perhaps insect pests.

"This bacterium can also produce antimicrobial chemicals that can kill microbial pathogens, thereby protecting the crop," says Dr. Yuan. "It could in the future be used to develop natural pesticides in disease prevention or treatment in agriculture."

The discovery was made using lab techniques that isolate bacteria for study and application in agriculture. Plant root bacteria are of particular interest because they could lead to clues about improving plant growth sustainably, Dr. Yuan noted.

The modern molecular technology allows the bacteria to be studied at the molecular level. Paenibacillus polymyxaCR1, for example, was the first bacterial genome to undergo complete genome sequencing, the process by which all the genetic information of a bacterium is available for analysis, by AAFC.

"Genome sequencing will help us better understand (the bacteria’s) molecular mechanism and biology, and enhance scientific understanding of how bacteria can improve plant growth and antimicrobial production to fend off pathogens, diseases and pests," notes. Dr. Yuan.

The London Research and Development Centre is among AAFC's national network of 20 research centres. The Centre conducts research in the areas of genomics, biotechnology and integrated pest management (insects and plant diseases).