Localizing a-amylase gene expression in germinated rice grains

In situ hybridization was used to localize the sites of expression for two a-amylase genes (RAmy1A and RAmy3D) in rice (Oryza sativa L.) over five days of germination. Messenger RNAs from both genes were initially detected in the scutellar epithelium and appeared at later stages of germination in the aleurone layer. RAmy3D mRNA reached its peak of accumulation 2 days(d) earlier in the scutellar epithelium than RAmy1A mRNA. Both mRNAs continued to accumulate in the aleurone layer up to 5 d of germination, although RAmy1A mRNA reached significantly higher levels than RAmy3D mRNA. Overall, the aleurone layer was responsible for producing the majority of the total grain a-amylase mRNA.