Abstract
Rice α-amylases were known to be encoded by multigene, and 11 isoforms were identified and characterized in the germinating seeds and tissue culture.α-Amylase I-1 (RAmy1A) was a glycoprotein bearing N-linked carbohydrate chain, that was actively synthesized and secreted from the secretory tissues. Here, we analyzed the transgenic rice seeds transformed with p35SΩ-α-amylase I-1 cDNA. The obtained transgenic rice lines had 2-5 copy of the exogenous gene. Most of them exhibited the co-suppression of α-amylase I-1. The co-suppression lines showed a marked delay of germination and seeding growth compared with the wild-type seed, however, supplementation of sucrose did overcome its abilities. Interestingly, it was observed that starch markedly accumulated in the bottom part of second leaf of transgenic seedlings, suggesting that α-amylase I-1 is involved in the accumulation and degradation of starch in the second leaf of germinating rice seeds.
