Localizing a-Amylase Gene Expression in Germinated Rice Grains

In situ hybridization was used to localize the sites of expressionfor two a-amylase genes (RAmy1A and RAmy3D) in rice (Oryza sativaL.) over five days of germination. Messenger RNAs from bothgenes were initially detected in the scutellar epithelium andappeared at later stages of germination in the aleurone layer.RAmy3D mRNA reached its peak of accumulation 2 days(d) earlierin the scutellar epithelium than RAmy1A mRNA. Both mRNAs continuedto accumulate in the aleurone layer up to 5 d of germination,although RAmy1A mRNA reached significantly higher levels thanRAmy3D mRNA. Overall, the aleurone layer was responsible forproducing the majority of the total grain a-amylase mRNA. (Received July 27, 1991; Accepted November 6, 1991)