Properties of a protein associated with metal toxicity in wheat

In previous studies it has been demonstrated that aluminum toxicity induces changes in the pattern of proteins synthesized in wheat. One of the most conspicuous changes is the appearance of a new cytoplasmic protein, with a pI of 5.2 and 18.6 KD MW. This polypeptide, tentatively called alumitin, has been observed in five wheat cultivars, of differing sensitivity to Al, at concentrations that inhibit root growth. In the present study, 2D-PAGE was used to present evidence that a polypeptide with the characteristics of alumitin is induced in wheat cv Victory after 24h treatment of growth-inhibiting levels of Cu (8{mu}M) and Cd (100{mu}M). However, it is not induced by low pH (3.5), Ca deficiency, or heat shock (4h, 37C) treatments sufficient to inhibit root growth. These results suggest that alumitin represents a specific response to metal toxicity rather than a general response to environmental stress. Rate of synthesis and turnover of alumitin are currently being studied.