Grass is an extremely resilient plant in general. But a particular species of turfgrass – Paspalum vaginatum (colloquially known as seashore paspalum) – which has been used to pad soccer fields recently built in Qatar for the World Cup, can tolerate stresses diverse and lethal enough to rival cactuses or camels. Now, a team of researchers led by the University of Nebraska-Lincoln has argued that seashore paspalum may soon assist another goal – growing crops which yield more food with less of the fertilizer that imposes significant costs on farmers, ecosystems, and water resources.
Since mid-20th century, the application of fertilizers such as nitrogen and phosphorous has skyrocketed, in order to boost plant growth. However, the seashore paspalum does not seem to need much of these nutrients, a surprising feature which sets it apart from its close relatives such as corn and sorghum.
By analyzing this plant’s genes and gene expression, the scientists discovered that it responds to a lack of nutrients by nearly doubling its production of a sugary molecule called trehalose. Although corn and sorghum naturally churn out some of the same molecule, the researchers saw no change in its production among these two nutrient-starved crops.
Unfortunately, trying to increase trehalose in corn proved ineffective. “So I thought about it in the opposite way,” said study lead author Guangchao Sun, a bioinformatician at the Mayo Clinic. “If I cannot supply trehalose to the plants, what if I stopped its degradation in those plants?”
By using an antibiotic that can inhibit the enzyme responsible for degrading trehalose, the scientists finally succeeded in cranking up the trehalose levels in corn and, within days, the crops started growing more. According to Sun and his colleagues, these changes also relied on autophagy – a “recycling program” in plant cells that takes apart old or damaged proteins, then reassembles them into new, functioning ones.
Eventually, the team managed to develop a mutant of corn which lacked the ability to engage the final stage of recycling. Moreover, even with a surplus of trehalose, the mutant failed to thrive when deprived of essential nutrients such as nitrogen or phosphorous, marking autophagy as an equally important facet of the resilience.
According to Sun, there are still other things to do before scientists will clearly understand seashore paspalum’s world-class tolerance. However, he hopes that very soon his team will manage to identify the genes that code for higher trehalose.
“And if you could (introduce) that genomic region into other elite corn varieties — say, some maize that has high yield but is really sensitive to nutrient stress — maybe now you get both a high yield and high resilience,” he concluded.
The study is published in the journal Nature Communications.
By Andrei Ionescu, Earth.com Staff Writer
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