Abstract: 【Objective】 The research was carried out to explore the molecular basis of the differential expression of GA-induced stem elongation genes of sugarcane and isolation of elongation-related genes. 【Method】 The plants were sprayed with gibberellin (GA3) at concentration of 200 mg?L-1 at early elongation stage, with water spraying as control. After extraction, equal quantity of the total RNAs of the same treatment was mixed to get two different mixed RNA pools for the GA3 treatment and the control. By cDNA-SRAP technique, different expressions of the genes were analyzed. 【Result】 Using 700 pairs of primers, about 15 000 cDNA fragments in size between 50-750 bp were amplified. Some fragments were different between the GA3 treatment and the control for different gene transcriptions in the young stem of sugarcane. Among them, 134 different cDNA fragments were selected. After reverse Northern blot analysis, 24 positive S-TDFs (cDNA-SRAP transcript derived fragments) were selected for cloning and sequencing analysis. After BLAST analysis, the 24 S-TDFs were divided into six categories according to gene function: energy and metabolism-related genes (4, accounting for 16.67%), genes of unknown functional proteins (6, accounting for 25%), unknown genes (10, accounting for 41.66%), cell wall biosynthesis and modification related genes (2, accounting for 8.33%), and transcription factor-related genes (1, accounting for 4.17%). 【Conclusion】 This study shows that the cDNA-SRAP technique is applicable to the analysis of gene differential expression. Some fragments of differentially expressed genes associated with sugarcane stem elongation were obtained, and may be used for investigating the molecular mechanism of sugarcane stem elongation.

Key words: gibberellin, sugarcane, cDNA-SRAP, differential expression