FeSensor · Finding the iron sensing protein in crop plants
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2015-05-01 → 2017-04-30
- EU contribution
- €183,455
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
Lines connect the coordinator with its partners.
Results in brief
Finding the iron sensing protein in crop plants
Iron (Fe) is needed for all living organisms. Iron deficiency anaemia is the most widespread nutritional disease in humans and Fe is a limiting factor for crop growth on many arable soils. However, in excess, Fe can cause serious oxidative damage and induce cell death. Therefore, uptake and accumulation need to be tightly regulated and cells must be able to sense Fe levels. The Fe sensing mechanism is well characterized for bacteria, yeast and mammals, but it is still not known in plants. This gap in our knowledge limits the possibilities to manipulate iron levels in edible parts of the plant without causing toxicity symptoms in the rest of the plant, a major goal for biofortification efforts. The overall aim of the project is to unravel the iron sensing mechanism in plants. In a previous study I discovered two genes that may be involved in signalling the iron status of the plant cell. In the project proposal, the genes were provisionally named IRS1 and IRS2, for Iron-Regulated Sensor, but during the project they were renamed BTSL1 and BTSL2 for BRUTUS-Like 1 and 2, based on homology to a gene called BRUTUS that was previously described in the model plant Arabidopsis. The BTSL proteins have several putative Fe binding domains, known as hemerythrin domains, and a RING Zn-finger domain that is likely to mediate protein-protein interactions. The objectives of the project were (i) to test the Fe binding properties of the hemerythrin domains of BTSL1 and BTSL2; (ii) characterize Arabidopsis plants lacking functional BTSL1/2 for iron homeostasis phenotypes; (iii) to screen for mutants disrupted in Fe homeostasis. The results showed that BTSL1 and BTSL2 are able to bind Fe through their hemerythrin domains. Double knock-out lines of BTSL1/BTSL2 failed to regulate Fe uptake, leading to an excess of iron in the plant. A collection of mutants to screen for defects in Fe homeostasis has been produced and interesting lines are currently being selected for further characterization. The main conclusion of this Marie Sklodowska Curie action is that I have identified two proteins, BTSL1 and BTSL2, that play an important role in the Fe sensing mechanism of dicotyledonous plants.
Data: CORDIS, © European Union
Project objective
Iron (Fe) is needed for all living organisms but in high concentrations within the cell it is toxic, therefore balancing the physiological level of iron is essential. Although the Fe sensing mechanism has been described for a wide variety of living forms, from bacteria to mammals, no clear information about how plants sense Fe is available. Whether or not Fe is sensed in roots or in shoots or in both, the chemical form of the Fe or the identity of the sensing protein, remains unknown. In yeast and mammals, Fe is sensed via Fe-S proteins, but in plants the Fe sensing mechanism has been shown to be independent from Fe-S cluster assembly in the mitochondria or cytosol. Using comparative transcriptomics in two model plant species I have identified a small family of genes (IRS1, IRS2 and BTS) that are good candidates for the plant Fe sensors. I would like to investigate if their putative Fe binding motifs, haemerythrin and rubredoxin, are functional in an Fe-sensing capacity. Moreover, I will investigate if the proteins have ubiquitination activity as predicted, and tissue-specific expression compatible with a double sensing mechanism in roots and leaves. Other possibilities for the Fe-sensing mechanism will be explored by using mutants defective in Fe-S assembly in the plastids, and unknown candidates will be uncovered with an unbiased mutant screening. Perturbing the Fe sensing mechanism in a tissue-specific manner would be a smart way of increasing the Fe content without causing toxicity symptoms in the rest of the plant.
Original text from CORDIS.
Participants
- UNIVERSITY OF EAST ANGLIA · NorwichCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union