The role of the vasculature in iron allocation and sensing in plants

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Most of the human population rely on plant-based products as the major dietary source for nutrients including iron (Fe). In terms of food security, and besides struggling to solve the problem of producing enough food for the rapidly growing population, we are also in need of finding solutions to fight the so-called "hidden hunger" or micronutrient deficiencies. Among the different micronutrient deficiencies, Fe is the most studied one in both plants and humans (1). This is because Fe serves as a cofactor in many critical biological processes and cellular redox reactions. Plants also require Fe for the synthesis of chlorophyll. Thus, Fe deficiency can lead to plant chlorosis and reduction in yield as a result of a decreased photosynthetic capacity. In crop plants like soybean, Fe deficiency chlorosis can cause up to 30% reduction in yield (2-4). In humans, Fe is required for hemoglobin molecules to transport oxygen. Lack of Fe in humans leads to anemia and it is a major cause for birth defects and many physical and mental illnesses. This is true not only in developing countries, where people mostly rely on plant-based food. In developed countries, Fe-deficiency anemia can also affect people whose diets heavily rely on highly processed foods, which are energy dense and micronutrient-poor. By number, moderate to severe anemia in the U.S. population increased from 1.0% to 1.9%, comparing data of 2003-2004 to 2011-2012 census (5). Because Fe is essential for both plants and humans and importantly, humans rely on dietary Fe from crop plants, understanding the mechanisms controlling Fe uptake, accumulation and Fe-deficiency response in plants may have a positive impact on both plants and human health. For this long-term goal, it is necessary to develop and establish different approaches to unravel the mechanisms that plants use to control iron uptake and allocation. By filling the gap in our knowledge of plant responses to Fe-deficiency, we will be one step closer to enhance the Fe concentration in crop plants and perhaps, we will make them more resilient to Fe-limiting conditions.