Mary Lou Guerinot
Deficiencies of micronutrients commonly limit plant growth and crop yields. Furthermore, as most people rely on plants as their dietary source of micronutrients, plants that serve as better sources of essential nutrients would improve human health. We combine genetics, high-throughput elemental analysis via inductively coupled plasma mass spectrometry (ICP-MS) and high resolution imaging via synchrotron X-ray fluorescence (SXRF) to identify and characterize genes involved in metal uptake, distribution and storage. We have characterized a number of Arabidopsis mutants that have increased tolerance to iron-deficient growth conditions and have increased iron accumulation relative to wild type plants. One of these has a similar metal content to wild type when grown on normal soil, but thrives on alkaline soil, accumulating significantly more iron in its shoot and seeds. A triple mutant of three closely related negative regulators of the iron deficiency response has increased tolerance to iron deficient growth conditions and increased iron accumulation without resulting toxicity. We have also uncovered unique patterns of iron and manganese localization in seeds and have now shown that VIT1 and MTP8 are responsible for setting up these patterns, allowing us to determine whether the patterns are biologically significant and whether they can be altered in support of biofortification of staple crops. We are continuing to work on determining the function of various members of the ZIP family of metal transporters, many of which are functionally redundant. We have now shown that two members are involved in unloading of zinc from the xylem and its sequestration in trichomes. Under high zinc conditions, doube mutant plants store substantially less zinc in their trichomes and display veinal chlorosis of rosette leaves, likely as a result of their failure to unload zinc from the xylem as efficiently as wild type.
The asset you are trying to access is locked. Please enter your access key to unlock.