A new study, the product of a research-industry alliance, has highlighted an innovative and eco-friendly way of putting crop diseases in check by enlisting the help of bugs already present in the soil.
The research showed that some strains of Pseudomonas bacteria can protect the potato crop from destructive diseases. Researchers found that certain small molecules are crucial for guarding against potato scab, a disease responsible for significant losses of harvests.
Common potato pathogens that often bring about major crop losses include Streptomyces scabies and Phytophthora infestans. The latter played a key part in the Great Famine that was witnessed in Ireland.
Researchers have before now explored Pseudomonas as biological control agents for plants. These bacteria produce natural substances that not only help to suppress bugs but also boost plant growth.
The new Agri-tech method proposed in this study, which appeared in eLife, could help to both cut the cost of preventing diseases and reduce damage to the environment.
This study was led by researchers from John Innes Centre (JIC), which is located in Norwich, England.
Pathogen suppression in potatoes
In this research, scientists isolated hundreds of Pseudomonas bacteria strains from commercial potato field soil and analyzed them. They carried out genome sequencing on 69 of the isolated strains.
The team was able to identify a vital mechanism that enabled some strains to shield the potato crop from damaging bacteria. This discovery was aided by comparing strains that suppress the activity of pathogens to strains that did not.
The research shows that the production of tiny molecules known as cyclic lipopeptides plays a crucial role in preventing potato scab.
These molecules have dual roles. First, they produce an antibacterial effect that helps to contain the bacteria responsible for potato scab. Second, they enable beneficial Pseudomonas to move more freely and take control of the roots of plants.
Researchers further observed how irrigation can cause huge changes to the population of genetically diverse Pseudomonas bacteria population in the soil.
These findings build on previous research showing the potential of Pseudomonas for suppressing potato scab biologically. It was also known before now that irrigation could aid in suppressing Streptomyces scabies disease. This research makes clearer how this happens.
A new approach for tackling diseases
The research team proposed a new method that involves the use of high-speed genetic sequencing to screen the microbiome of crop fields. The screening considers diverse agronomic, soil, and environmental conditions.
This approach can make it possible to check the soil microbiome to detect useful bacteria that are present. It can also identify the molecules that are being produced to control disease-causing bacteria.
“The approach we describe should be applicable to a wide range of plant diseases because it is based on understanding the mechanisms of action that are important for biological control agents,” said Dr. Alba Pacheco-Moreno, the first study author.
According to John Innes Centre group leader Dr. Jacob Malone, a benefit of this method is that it entails using bacteria that are already present in the environment. The risk of ecological damage is thus reduced.
The protective strains obtained from the environment will be put back into the same site they were taken from. They will be added back in greater numbers or in mixed cocktails of beneficial strains as soil microbiome boosters.
The means by which these boosting treatments could be applied include as seedling coatings or through spraying. They may also be put into use by way of drip irrigation.
The researchers disclosed that molecules produced by protective Pseudomonas will no longer be used at some point. Instead, the bacteria themselves would be used as they provide a more sustainable means of protecting crops.