Researchers from the University of East Anglia and collaborators report that naturally occurring soil bacteria may help crops survive in increasingly saline farmland, a growing agricultural problem linked to climate change, irrigation practices and rising sea levels. The team, led by Dr. Yanfen Zheng, said the bacteria significantly improved plants' ability to cope with salt stress and identified a mechanism that differs from long-standing assumptions about how plants tolerate salinity. The findings were published in Science Advances.
The study examined root microbiomes from multiple crop species grown in different soil types and found that pseudomonads consistently accumulated around roots exposed to salt stress. The same pattern was observed in maize, tomato and rapeseed, which the researchers said suggests the response is not limited to a single crop. Genetic analysis indicated that these bacteria carry traits that help them survive high-salt environments, including sodium transport systems and other stress-resistance mechanisms.
To test their effect, the researchers introduced selected pseudomonad strains to soybean plants. In greenhouse experiments and field trials, the bacteria colonized the roots and were associated with stronger root systems, improved plant development and higher yields under salty conditions compared with untreated plants. The researchers said this points to potential agricultural applications for land where salinity has reduced conventional crop performance.
The team said the most unexpected result was that the bacteria did not appear to protect plants by lowering sodium levels inside plant tissues. Instead, they reported that the microbes stimulated the production of lignin, a structural compound in plant cell walls that helps reinforce tissues under stress. Roots of bacteria-treated plants showed lignin increases of more than 30 percent in some measurements under salt stress. The researchers also identified genes linked to that response, and said plants engineered to overexpress those genes performed better in salty soil, while plants unable to produce lignin did not gain the same benefit from the microbes.
The researchers argue that the work could open a path toward bio-based treatments that help farmers grow crops in saline soils without heavy chemical inputs. Professor Jonathan Todd said microbial approaches could become an important tool for protecting yields and food security as more farmland is affected by salt buildup. The materials did not include an independent critical assessment of the study, and no external experts were cited challenging the findings or their potential applications.