ARS | Publication request: COMPARTMENTATION OF CADMIUM IN HIGH- AND LOW- CD ACCUMULATING, NEAR ISOGENIC LINES OF DURUM WHEAT

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 19, 2004
Publication Date: July 24, 2004
Citation: Hart, J.J., Welch, R.M., Norvell, W.A., Kochian, L.V. 2004. Compartmentation of cadmium in high- and low- cd accumulating, near isogenic lines of durum wheat. American Society of Plant Biologists Annual Meeting. p. 256.

Technical Abstract: Durum wheat grains produced in the Great Plains region of North America can contain levels of cadmium (Cd) that exceed proposed international trade standards. Therefore, understanding physiological factors related to excessive Cd accumulation in durum wheat is desirable. We have used two near-isogenic lines of durum wheat that differ approximately three-fold in grain Cd accumulation. Studies with hydroponically-grown seedlings showed that the two isolines did not differ in root Cd uptake. However, the rate of translocation of Cd from roots to shoots was higher in the high-Cd accumulating isoline. A study of whole plant partitioning showed that the low-Cd accumulating isoline retained more cadmium in roots beginning at the earliest stages of growth. In comparisons of partitioning of Cd and other metal micronutrients including Zn, the differential partitioning between the two isolines was shown to be specific for cadmium. Experiments with gel filtration of root extracts suggest that the Cd in roots of both isolines is associated with high and low molecular Cd-binding complexes containing phytochelatins (PCs). The differential partitioning of Cd between the two isolines appears to be related to complexation of Cd with PCs and compartmentation in the vacuole. The function of the gene(s) associated with low Cd accumulation may therefore be related to PC synthesis or transport of Cd and/or Cd-PC into the vacuole.