Research highlights the impacts of biomolecules in plants over stress

Diphthamide is a biomolecule required for the correct synthesis of proteins in cells. When diphtheria infects a person, the diphtheria toxin modifies diphthamide, which may lead to compromised protein synthesis and potentially fatal effects. Up until this point, only fungi and mammals were known to produce diphthamide.

Now, it has been shown that the biomolecule also exists in plants by a study team led by Professor Ute Krämer, who holds the Chair of Molecular Genetics and Physiology of Plants at Ruhr-Universität Bochum. Additionally, the researchers demonstrated that certain environmental conditions may have an impact on its creation. On July 11^th, 2022, this was published in the journal Nature Communications.

The research was conducted at Ute Krämer’s department with assistance from Professor Lorenz Adrian at the Technical University of Berlin and Professor Raffael Schaffrath’s research group at the University of Kassel, as well as other research groups in Germany.

Plants without diphthamide grow less

A natural alteration of the so-called elongation factor-2 protein found in many organisms is the biomolecule diphthamide. This protein is one of the elements that the cell uses to assemble all of the other proteins.

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. Bacterially caused diphtheria infections have been documented since ancient times and were greatly feared until the 19th century, before a vaccine was developed.”

Ute Krämer, Professor and Chair, Molecular Genetics and Physiology of Plants, Ruhr-Universität Bochum

As a model organism for medical study, baker’s yeast and animal species were the only ones where diphthamide had previously been found and extensively investigated. The work of Ute Krämer’s team has now shown that diphthamide is produced in plants as well and serves an essential purpose.

If a plant lacks the capacity to produce diphthamide, the rate of protein biosynthesis errors increases. Furthermore, since cell division is reduced, plant development is also slowed down. The growth limitation may be brought on by a number of other changes in key cellular regulatory mechanisms.

Stress influences diphtamide formation

The study’s findings indicate that the crucial first step in the production of diphthamide, which is known to occur in mammals and yeast, also occurs in plants. This implies that it was also the case for the following processes that resulted in the diphthamide that has recently been found in plants.

What is completely new, however, is that not only genetic defects can lead to a loss of diphthamide. Environmental stress, especially an excess of the nutrient trace element copper or the environmental toxin cadmium, also inhibits diphthamide formation in plants.”

Ute Krämer, Professor and Chair, Molecular Genetics and Physiology of Plants, Ruhr-Universität Bochum

Human cells likewise showed a lack of diphthamide in the presence of high copper concentrations. These discoveries point to a new component that affects plant development rates and may help us understand how diseases spread.

It now needs to be investigated whether plant pathogens also use diphthamide as an Achilles heel–just like the diphtheria pathogen does in humans.”

Ute Krämer, Professor and Chair, Molecular Genetics and Physiology of Plants, Ruhr-Universität Bochum