Abstract
We have identified N6D medium with 10% glucose promoted starch accumulation in rice callus. During this condition, AGPase large subunit gene (accession D50317, AGPL) was increased in proportion to the starch accumulation. To clarify the starch-accumulation mechanisms in callus, we firstly analyzed transcriptional responses of starch and sugar metabolic genes to sugar in the medium. Nine of starch and nine of sugar metabolic gene expressions were analyzed by Quantitative RT-PCR. According to expression pattern, these genes were divided into six groups: 1) increased or 2) decreased in proportion to starch contents, 3) just induced or 4) suppressed by sugar contents, 5) ubiquitous, and 6) very low. There was no gene, which shows the expression pattern such as AGPL. These results suggested AGPL is key enzyme of starch accumulation in callus. We will investigate the regulation factor for expression of AGPL gene in this condition.
