GA3-regulated cDNAs from Hordeum vulgare leaves.

The barley mutant dbg 576 shows an extreme vegetative dwarf phenotype. This is reversed after the application of GA3 which also induces the mutant florets to become partly fertile. cDNA clones ES1A and ES2A were isolated by differential screening with subtracted probes from a DNA library prepared from mutant leaf blades after GA3 treatment. Both the ES1A and the ES2A mRNA level increases as early as 30 min after GA3 treatment and decreases later. Accumulation of ES1A and ES2A mRNAs is leaf blade-specific and both are ca. 750 nucleotides long. ES1A encodes a protein of approximately 6 kD which shows a significant homology with mammalian epidermal growth factors (EGFs). ES2A encodes a protein of 22 kDa with homology, in regions with potential amphiphilic helices, with the D7 family of late embryogenesis-abundant proteins (LEA).