COMPARISON OF SUCROSE METABOLISM AND GENE EXPRESSION IN TWO DIVERSE SACCHARUM GENOTYPES

摘要

Differences in sucrose metabolism may contribute to differences in sucrose accumulation among Saccharum genotypes. Gene expression and sucrose metabolism were studied in a high sucrose genotype, 'Green German' (GG), and a low sucrose genotype, 'IND81-146' (IND). Sucrose and total sugar concentrations of the two genotypes were similar in elongating internodes. Sucrose stopped accumulating during internode maturation in IND so that mature internodes of GG had much higher total sugar and sucrose concentrations than IND. Activities of soluble acid invertase, neutral invertase, sucrose synthase and sucrose-phosphate synthase were not different between genotypes. Analysis of gene transcription by northern analyses of total RNA showed that, in GG, transcripts of a soluble acid invertase gene disappeared after internode elongation, coincident with the onset of sucrose accumulation, while in IND expression of this gene persisted in all internodes. Northern analysis supports the hypothesis that differences in sucrose metabolism result in differences in sugar accumulation in Saccharum genotypes.