Snapshots of Life: From Arabidopsis to Zinc
Posted on by Dr. Francis Collins
To most people, the plant Arabidopsis thaliana might seem like just another pesky weed. But for plant biologists, this member of the mustard green family is a valuable model for studying a wide array of biological processes—including the patterns of zinc acquisition shown so vividly in the Arabidopsis leaf above. Using synchrotron X-ray fluorescence technology, researchers found zinc concentrations varied considerably even within a single leaf; the lowest levels are marked in blue, next lowest in green, medium in red, and highest in white, concentrated at the base of tiny hairs (trichomes) that extend from the leaf’s surface.
A winner in the Federation of American Societies for Experimental Biology’s 2015 BioArt competition, this micrograph stems from work being conducted by Suzana Car and colleagues in the NIH-funded lab of Mary Lou Guerinot at Dartmouth College, Hanover, NH. The researchers are still trying to figure out exactly what zinc is doing at the various locations within Arabidopsis, as well as whether zinc concentrations are constant or variable. What is well known is that zinc is an essential micronutrient for human health, with more than 300 enzymes dependent on this mineral to catalyze chemical reactions within our bodies.
Nearly one-fifth of the world’s population suffers from mild to moderate zinc deficiency, which can impair the immune system, stunt growth, and affect gastrointestinal function. The problem is most severe in places where people eat primarily plant-based diets. So, the hope is that, as the Dartmouth group and others learn more about the fundamentals of how plants acquire and process zinc and other minerals, it will lead to new ways of optimizing levels of vital micronutrients in soybeans, corn, rice, and other staple crops.
Model Organisms for Biomedical Research: Arabidopsis (NIH)
Zinc: Fact Sheet for Consumers (NIH)
Guerinot Lab (Dartmouth College, Hanover, NH)
BioArt (Federation of American Societies for Experimental Biology, Bethesda, MD)
NIH Support: National Institute of General Medical Sciences; National Institute of Environmental Health Sciences
I ask this knowing that the question will probably only point to my lack of knowledge on the subject but I’m curious to know if it’s possible that it’s not so much to do with zinc acquisition and storage but exposure to sunlight depleting the stores of zinc in the longer-exposed upper portion of the leaf?