THE EXPRESSION OF ALUMINUM STRESS-INDUCED POLYPEPTIDES IN A POPULATION SEGREGATING FOR ALUMINUM TOLERANCE IN WHEAT (TRITICUM-AESTIVUM L)

This study examined the changes in gene expression induced by aluminum (Al) stress in wheat root tips. Seedlings of Triticum aestivum L. cvs . Katepwa (Al sensitive), Maringa (Al tolerant), and Alikat (Al tolera nt near isoline; 'Katepwa'3/'Maringa') and a F-2 population derived f rom 'Katepwa' x 'Alikat', were grown for 3 days in either 0 or 1 mu g . mL(-1) Al. Polypeptides were labeled with S-35-methionine prior to s eparation by gel electrophoresis. There were a few polypeptides from w hole cell lysates that showed enhanced expression in all of the genoty pes in 1 mu g . mL(-1) Al, however, the whole cell lysate and microsom al polypeptide profiles also revealed numerous unique changes in gene expression in Al-sensitive 'Katepwa' at 1 mu g . mL(-1) Al; the latter cosegregated with only the Al-sensitive F-2 bulks. The microsomal pol ypeptide profiles of the Al-tolerant lines 'Maringa' and 'Alikat' chan ged marginally in the presence of Al and these changes were also refle cted in the Al-tolerant F-2 bulks. The data showed that there were man y changes in gene expression which cosegregated with Al sensitivity an d suggest that Al tolerance in wheat may rely on constitutively expres sed polypeptides.