We all know the earth’s surface is about 71% water. However, 96.5% of that water is in the oceans, and that water isn’t necessarily usable by all of land-dwellers, whether we’re plants or animals, mostly because of the salt.

In some recent, very intriguing science news, it’s been discovered that a certain bacterium living inside the roots of some plants allows them to grow well despite salty conditions. It turns out their “secret weapon” is triggering sulfur metabolism. This discovery is already helping researchers develop new technologies that facilitate the irrigation of crops with salty water. This is an important prospect for regions – like the American West – that become more and more dependent on energy-intensive desalination for fresh water.

It should be noted that not all bacteria are bad. Some beneficial bacteria interact with their plant hosts to help them thrive while also promoting plant growth. Back in 2013, plant scientist Heribert Hirt of King Abdullah University of Science and Technology (KAUST) in Saudi Arabia – also an extremely arid region – founded the Darwin21 project, with the goal of using desert plant bacteria to improve agricultural sustainability in very dry lands. That project found a bacterium called Enterobacter sp. SA187, which can make crops resistant to various stresses including heat, drought and salt tolerance. Awesome, right?

The research team treated the plant Arabidopsis with a specially selected strain of bacteria to boost their growth in stress conditions. The smaller plant on the left is the control and the plant on the right is the bacteria-treated plant. Photo courtesy of KAUST

Hirt’s team has now analyzed the genetic and metabolic changes that happen inside SA187 when they interact under salt-free and salt-stressed conditions.

What usually happens when plants are exposed to too much salt is their cells release reactive oxygen species, which in turns causes cell damage, and that leads to reduced plant growth and crop yields. The researchers found that salt stress triggers sulfur metabolism in SA187 bacteria living inside roots. Sulfur metabolites are released, which feed sulfur metabolism, and a critical antioxidant called glutathione is created. Glutathione detoxifies the plant from salt-induced reactive oxygen species, enabling it to grow despite the stress.

“Another key finding of our investigations was that we can replace the protective function of SA187 against salt stress damage of the plant by directly adding sulfur metabolites, opening up the possibility to use probiotics in agriculture,” said Hirt. That’s right, probiotics can be good for many living things.

According to the Sulphur Institute, sulfur is essential for the growth and development of all crops, without exception. Like any essential nutrient, it has some key functions in plants, including the formation of chlorophyll which helps with photosynthesis, which is how plants produce starch, sugars, oils, fats, vitamins and other compounds.

Hirt is now working on establishing a startup with his colleagues that aims to provide breakthrough technologies that can treat seeds or crop plants with SA187, saving farmers in arid areas money and making saline agriculture an actual practice.