How do plants protect themselves from oxidative stress during iron intake, and why is this important for humans too?

Iron is a critical micronutrient for the survival of plants and humans, but too much iron can also be toxic. An interdisciplinary research team from the Heinrich Heine University Düsseldorf (HHU) has discovered that the PATELLIN2 protein is not only involved in the regulation of iron levels in plants.

PATELLIN2 is one of a group of proteins also involved in the transport of vitamin E in humans. The researchers published their findings in the journalism, which is also important for providing people with iron through plant foods. Plant Physiology.

Iron is an essential micronutrient for humans. Deficiencies of iron and zinc in a person’s diet cause serious harm to health, first of all, in the unborn and young children. Therefore, in order to secure the world’s food supplies and combat malnutrition, especially in the poorest countries, it is necessary to obtain iron primarily from plant sources and improve it through targeted cultivation.

Plants need iron for basic metabolic reactions such as photosynthesis and respiration. However, iron is a double-edged sword for them: Unfavorable environmental conditions such as drought can put plants under stress, exacerbated by the presence of reactive metal ions, including iron. Rooted plants obviously cannot escape local stress conditions, so land plants had to develop other ways to deal with stressors.

These include iron regulation. For research and practice, it is important to understand how plants manage their micronutrient nutrition during their growth with the potentially risky consequences of oxidative stress. If we know these processes, we can affect them in a targeted way to improve plant productivity and food quality, especially in light of climate change that increases the likelihood of drought.

Consisting of representatives of biology, chemistry and medicine at HHU, Professor Dr. Petra Bauer and Chair of Botany Dr. A team led by Rumen Ivanov studied the mechanisms of iron uptake in plants using Arabidopsis thaliana (thale cress) as a model plant. The iron-regulated transporter IRT1 plays an important role in iron uptake in plant roots.

Stem cells control the activity of IRT1, enabling plants to limit toxicity and oxidative stress caused by metal ions. The HHU researchers were able to show that the so-called SEC14 domain of IRT1 binds the lipid transfer protein PATELLIN2. This changes the protein environment of IRT1 depending on the iron source.

Another lipid transfer protein with the SEC14 domain plays a key role in vitamin E homoeostasis in humans and in the transport of vitamin E from the gut through the liver to various organs in the body. The body gets vitamin E from plant foods, especially leaves and seeds.

PATELLIN2 can bind the alpha-tocopherol molecule, one of the most important vitamin E compounds in leaves and roots. Jannik Hornbergs, who conducted the work during his PhD. At HHU, Dr. “We determined that the SEC14 lipid transfer protein PATELLIN2 and tocopherols are critical for iron mobilization and antioxidant activities in the root as a reaction to iron,” says Karolin Montag.

The link between iron transport and the lipid transfer protein SEC14 provides new working models of how cells can use vitamin E to control the extent of iron-induced oxidative stress. Dr. Rumen Ivanov and Professor Bauer on the significance of the results: “Ultimately, these connections that we now know can be used to identify new breeding targets for crop plants that can achieve stress resistance in plants and maximize iron content in plants.”