Climate changes is of major concern worldwide as it result in an average global temperature increase. Heat decreases water availability, leading to longer periods of drought. Hence, an increase of only 1°C can (and is) already significantly impact on global crop production. Since decades, research strategies focus mainly on genetic engineering of molecular markers or screening for cultivars inheriting increased drought tolerance. It has been shown, however, that most of these tolerant genotypes, are often less efficient in growth and yield. Hence there is need to understand the mechanism(s) that enable stress tolerance concurrent with optimal growth performance. A trait, the so called staygreen phenotype, has been shown to be a good marker for drought tolerance. It characterizes a crop that, under drought stress conditions, keeps chlorophyll levels high. This leaf maintenance strategy protects plants from leaf-abscission and allows for a rapid recovery upon rewatering. In recent years, more and more research present evidence that habitat adapted symbioses of plants with soil microbes increases their abiotic stress tolerance while at the same time maintaining growth performance.
We recently demonstrated that the association of legumes with nitrogen fixing soil bacteria induces a staygreen phenotype in drought stressed Medicago plants. Major changes in the leaf proteome of the symbiotic primed plants (“symbioproteome”) involved in stress protection, indicate the complexity of this mechanism. Our current investigations give evidence to the hypothesis that ferritins are strongly involved in this symbiont induced leaf maintenance effect. Ferritins are known as iron storage and mobilization proteins, involved in leaf senescence and drought response. Our unpublished data revealed that ferritin is also crucial for symbiosis formation, which has not been shown thus far and needs further investigation. We therefore propose, iron is not only an important nutrient for plant growth but also crucial for nodule formation, symbiosis functioning and priming of drought tolerance. Understanding the function of Ferritin will enable smart breeding towards improved crop yield and food protection upon water scarceness.
Hence, in this project, we want to understand the mechanism of the ferritin dependent cross talk between nodule development, functioning and drought tolerance. Our approach includes reversed genetics and a comprehensive integration between multiple levels of molecular and physiological phenotyping strategies comparing different genotypes and natural accessions.
