The proper formation of proteins is dependent on the biomolecule diphthamide. Diphtheria can cause severe complications in humans if diphthamide is not formed properly. Diphthamide is a biomolecule that has only been discovered to be present in animals or fungi. The biomolecule is now also found in plants, according to a research team.
Researchers also found that certain environmental factors can affect its formation. This research was published in the journal. Nature Communications11 July 2022
The study was carried out in Ute Krämer’s department, with contributions from the research group of Professor Raffael Schaffrath at the University of Kassel and Professor Lorenz Adrian at the Technical University of Berlin, as well as other research groups in Germany.
Plants that do not have diphthamide will grow less
Diphthamide, a biomolecule that modifies the so-called Elongation Factor-2 protein in many organisms, is a natural modification. This protein is responsible for the building of all proteins in the cells. “This modification has long been known to be the target of diphtheria toxin, which can cause life-threatening complications in people infected with diphtheria by preventing the cellular synthesis of proteins,” explains Ute Krämer. “Bacterially-caused diphtheria infections were well-known since antiquity and were highly feared up until the 19th Century, when a vaccine was created.”
Diphthamide was previously only discovered and studied in animal organisms. Ute Krämer’s team has now shown that diphthamide is also formed in plants and performs an important function: if the ability to form diphthamide is missing in the plant, there is an increased error rate in protein biosynthesis. Reduced cell division also results in a reduction in plant growth. The growth restriction could also be caused by a number of other changes in the central cellular regulatory processes.
Stress influences diphtamide formation
The study revealed that plants are responsible for the first step in biosynthesis of diphthamide, which is also known from yeast and mammals. This suggests that plants are also responsible for the biosynthesis of diphthamide. “What is completely new, however, is that not only genetic defects can lead to a loss of diphthamide,” explains Ute Krämer. Diphthamide production in plants can also be inhibited by environmental stress, particularly excesses of the nutrient trace element copper and the environmental toxin, cadmium. Diphthamide deficiency was also seen in human cells when there were high levels of copper. These findings reveal a new factor that influences plant growth and could help us understand how diseases develop. “It now needs to be investigated whether plant pathogens also use diphthamide as an Achilles heel — just like the diphtheria pathogen does in humans,” says Ute Krämer.