New research from the John Innes Centre reveals an alarming potential for bacteria to spread diseases across a broader range of plant species than previously recognized. Using Pseudomonas syringae, a well-known plant pathogen, researchers identified its ability to infect both flowering and non-flowering plants through the toxin syringomycin.
Expanding Horizons of Pathogenic Spread
Traditionally, research on plant pathogens has focused on flowering plants, including staple crops. However, the John Innes team demonstrated that syringomycin, a toxin produced by highly infectious strains of P. syringae, causes severe tissue damage and stress responses in non-flowering plants like liverworts and ferns.
Surprisingly, non-flowering plants exhibited even greater susceptibility to the toxin than flowering species, highlighting the pathogen’s potential to colonize a diverse range of plants separated by over 500 million years of evolutionary history.
A Universal Mechanism of Virulence
Dr. Phil Carella, who led the study published in Cell Host & Microbe, explained the significance of these findings.
“Each plant species we studied has a different evolutionary trajectory, but a single group of pathogens can infect all of them using common pathogenicity factors,” said Dr. Carella.
The research suggests that P. syringae targets fundamental processes shared across the plant kingdom. Specifically, syringomycin appears to disrupt cell membranes, a mechanism effective against both simple, non-flowering plants and complex flowering species.
Reconsidering Non-Flowering Plants
Non-flowering plants are often viewed as less complex than their flowering counterparts, which evolved later. However, this study underscores their importance in understanding fundamental plant-pathogen interactions. The findings could lead to broader insights into protecting agricultural crops from diseases.
“Liverworts may not feed us, but they are invaluable for teaching us about core virulence mechanisms of critical pathogens,” Dr. Carella noted.
Implications for Crop Defense and Future Research
This research sheds light on the general adaptability of plant pathogens, posing both risks and opportunities for agriculture. Understanding the widespread virulence mechanisms of P. syringae could inspire new approaches to defending crops against diseases.
The next steps for the team include:
- Investigating how syringomycin promotes bacterial spread and works with other pathogenic proteins.
- Exploring why certain P. syringae strains lack the toxin.
- Expanding their plant diversity experiments to identify resistance traits.
By looking at the broader plant world, scientists hope to uncover universal mechanisms of pathogenicity and find ways to bolster resistance in vital food crops.
