Salty soil, one of the greatest threats to agriculture, may have a new remedy in the form of naturally occurring soil bacteria that allow plants to thrive under harsh conditions.
An international team led by Dr. Yanfen Zheng at the Chinese Academy of Agricultural Sciences presented their findings on increasing plant survivability in inhospitable environments in a recent paper published in Science Advances.
In their research, the international team demonstrated that maize, tomato, and rapeseed thrived in soil that would typically be unusable due to a previously unknown mechanism in these microbes, in a breakthrough for agriculture.
Salt and Agriculture
“The build-up of salt in farmland is a major and worsening problem – driven by climate change, irrigation and rising sea levels,” said co-author Prof Jonathan Todd, from the University of East Anglia’s School of Biological Sciences and the Quadram Institute on the Norwich Research Park. “Salt chokes plant growth, damages roots, and severely impacts entire harvests – putting global food supplies at risk.”
Agricultural scientists have long known that root microbiomes, the community of microbes living among a plant’s roots, are important for dealing with environmental stresses, yet they remained uncertain of the mechanics involved.
“We found that plants appear to recruit beneficial bacteria in salty soil conditions, which in turn trigger internal changes that strengthen their physical structure and resilience,” Todd continued. “If scientists can harness this natural process, it could mark the beginning of a new era in climate-resilient agriculture.”
Investigating Plant Root Microbiomes
The international team examined a variety of plant root microbiomes across different soil types and plant species, identifying pseudomonads, a type of naturally occurring soil bacterium, that are drawn to the roots of maize, tomato, and rapeseed in heavily salted environments. By noting the commonality of high salt content across a variety of crops, the researchers concluded that this was more than a mere coincidence and decided to analyze the genetic mechanisms behind the bacterium’s behavior.
“Compared to other microbes, pseudomonads carry specialised genes that help them tolerate high salt levels, including sodium transport systems and other stress resistance mechanisms,” Todd said.
Next, the researchers introduced various pseudomonad strains to soybean plants in laboratory and real-world soil experiments and observed that the bacteria colonized plant roots, resulting in increased growth in harsh, salty environments. Those soybean plants that received the bacteria demonstrated stronger root systems, more advanced development, and higher yields than those without.
“The most surprising thing was finding out how the bacteria helped plants cope,” Todd said. “For decades, it was thought that plants survive salinity by controlling sodium levels – essentially keeping harmful salt out. But we found no evidence that bacteria influenced sodium transport or ion balance.”
Lignin and Salt
“Instead of helping plants manage salt directly, the bacteria stimulated the plant to produce more of a substance called lignin,” Todd continued. “Roots of bacteria-treated plants showed a significant increase in lignin content, with some measurements rising by over 30 percent under salt stress.”
The tough, wood-like lignin acted as a shield against the salt, strengthening delicate tissues to endure a challenging environment. Unfortunately, in plants that couldn’t produce lignin, the pseudomonads produced no benefit. Building on the discovery, the researchers identified the genes in the plants involved in lignin synthesis and artificially overexpressed them to successfully confer salt resilience.
“We hope this discovery opens up new possibilities for agriculture,” Todd concluded. “With vast areas of farmland already affected by salinity and more under threat, microbial solutions could become an essential tool for maintaining crop yields and ensuring food security.”
The paper, “Pseudomonads Associated with Salt-Stressed Plants Facilitate Stress Adaptation of Soybean through Enhanced Lignin Biosynthesis,” appeared in Science Advances on June 24, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.