Genotype-specific heat shock proteins in two maize inbreds.

Leaf blade tissue of maize inbred lines B73 and Mo17 was analyzed for intraspecific genetic variability in the heat shock response. The maize inbreds were characterized for acquired thermal tolerance and patterns of heat shock protein synthesis. The leakage conductivity assay of membrane stability during stress indicated that Mol7 possesses greater potential than B73 to acquire thermal tolerance. Poly(A)(+) RNA, extracted from leaf blades, was translated in vitro in the presence of (35)S-methionine and the translation products separated by twodimensional gel electrophoresis. Major genotypic differences were observed in the translation products. Mo 17 synthesized twelve unique heat shock proteins in the 15-18 kD range, but B73 synthesized only three unique heat shock proteins in the same range. DNA polymorphisms were observed between the maize lines using (32)P labeled heat shock protein gene probes.