Yoneal Bless, whose research formed part of work to find ways to offset the harmful effects of heavy metals in the soil on food cropsCredit: Morgan Morris
Supplementing plants’ natural defence systems with signalling molecule methylglyoxal (MG) could potentially help offset harmful effects on food crops from heavy metals that have accumulated in the soil, a study in Scientific Reports suggests.
The research team, from the University of the Western Cape (UWC), South Africa, led by Marshall Keyster, grew radish (Raphanus sativus) in a soil enriched with small levels of MG. At low concentrations, MG plays an important role in triggering the plant’s ‘immune’ response when it experiences abiotic stresses such drought, heat, high soil salinity, or toxicity induced by heavy metals. The team found that by supplementing the plant’s own supply of MG, it aided the plant’s ability to reduce stress caused by the heavy metal zirconium (Zr). This breakthrough offers a potential solution to the problem of heavy metal contamination, particularly in regions like South Africa where zirconium production poses environmental concerns. The researchers found that complementing the MG available to radish restricted the movement of zirconium from the plant’s root to its shoots, improved both shoot growth and overall plant biomass.
An important finding of the UWC study was linking, for the first time, zirconium toxicity to the overproduction of what is known as reactive oxygen species (ROS), explains Yoneal Bless, the study’s first author. These molecules are important for maintaining normal plant growth, but when elevated, can cause stress in plant cells.
“What our study shows is the important role that MG can play in regulating levels of ROS when a plant is under heavy metal stress,” says Bless. While the study focused on seedling shoots only, work on more mature plants could shed further light on the value of MG treatment to improve crop resilience against heavy metal toxicity, she adds.
