Effects of Drought Stress on Soluble Proteins in two Maize Varieties

Drought stress was generated by PEG 6000. Water potentials were: zero as the control, and –0.15, –0.49, –1.03, and –1.76 MPa as treatments. After 24-h treatment the total soluble protein content of 2 maize (Zea mays L.) cultivars (704 and 301) was determined and SDS-PAGE gel electrophoresis in the first dimension was performed. By decreasing water potentials, total soluble protein content first increased, and then decreased in the roots and leaves of both varieties. The decrease in total soluble protein content in the roots of both varieties was equal, but in the leaves of cv. 301 it was greater than in cv. 704. In drought conditions the decrease in root and shoot fresh weight in cv. 704 was greater than in cv. 301. With water potential –1.76 MPa, the accumulation of dehydrin-like 38, 50, 57, and 65 KDa M.W. root proteins and 15, 17, 20, 27, 30, 37, 54, and 59 KDa M.W. leaf proteins increased. However, the expression of 15, 19, and 27 KDa M.W. root proteins, and 22 KDa M.W. leaf protein was induced in both varieties. The accumulation of dehydrin-like proteins in the roots and leaves of cv. 704 was higher than in cv. 301. There was no relationship between protein changes and drought tolerance.