David G. Mendoza-Cózatl, Ph.D.

Research

I am interested in understanding the molecular, biochemical, and mechanistic processes by which plants sense and accumulate nutrients but also toxic elements such as cadmium and arsenic. Plants and seeds are the main dietary source of essential elements like iron (Fe), zinc, and copper, not only for humans but also for livestock. Plant-based products are also the main entry point into the food chain for toxic elements such as cadmium and arsenic. Therefore, understanding the molecular mechanisms by which plants take up, mobilize, and accumulate essential metals and detoxify nonessential metals will have two major impacts on human health: (i) first, it will help to develop grains with enhanced nutritional value and (ii) it will ensure the accumulation of essential metals while avoiding the retention of nonessential ones.

Over the past decade, there have been significant advances in the molecular mechanisms that regulate iron uptake at the root level. Iron sensing, however, remains an active area of research with several hypotheses that need to be tested experimentally. Recent spatiotemporal gene expression analyses revealed that leaves respond faster to iron deficiency than roots. Moreover, under certain conditions, leaves and roots display opposite iron-related transcriptional programs, suggesting that leaves have autonomous mechanisms to sense iron. My lab is currently integrating leaf-specific time-series gene expression analyses together with targeted high-throughput DNA-protein and protein-protein interaction screens to identify transcriptional complexes necessary to regulate iron homoeostasis.

As an Innovation Fund investigator, David G. Mendoza-Cózatl, Ph.D., is teaming up with Clarissa J. Nobile, Ph.D., to study how plants and microbes interact in the context of iron uptake and utilization. Iron deficiency affects 30% of the world’s population and is thought to be the most prevalent nutritional deficiency in the world. Recent research indicates that microbes living in plants may benefit from iron extracted through roots; furthermore, plant molecules also seem to promote the colonization of beneficial microbes. Despite these advances in the field, it has not yet been established whether microbes play an active role in a plant’s response to iron deficiency. Combining expertise from Mendoza-Cózatl’s work in plant biology and Nobile’s research in microbial communities, the pair will dissect the plant-microbe relationship to understand how plants maintain iron homeostasis. They will use Arabidopsis thaliana lines developed from the Mendoza-Cózatl lab to examine how the presence of known microbial communities alter their response to iron deprivation. They will also determine how the composition of microbes present in the leaves and roots of plants are altered by the varying levels of iron. A greater understanding of this relationship could lead to solutions for addressing nutritional iron deficiency through the development of iron-fortified crops.