Pinellia ternata is one of the most important herbs in traditional Chinese medicine. Recently, its yield is hard to meet the market demand, therefore the system of in vitro micro-tubers was developed for its propagation and endogenous GA was revealed probably function negatively during micro-tubers induction. However, the mechanism is still unknown. In this study, 70 mg/L chlormequat chloride (CCC) was successfully used to inhibit the endogenous GA content and promote the micro-tubers induction. Subsequently, suppression subtractive hybridization (SSH) was performed to identify GA-related genes associated with in vitro micro-tubers formation in P. ternata. The cDNAs of micro-tubers induced with and without CCC were used as the “tester”, and “driver”, respectively. SSH library sequencing yielded 300 expressed sequence tags (ESTs). Finally, 226 ESTs were retained after screening, 84 of which had no significant homology to any of previously identified genes and 39 of the remaining 142 ESTs represented singletons. Real-time quantitative RT-PCR analysis of the expression patterns showed that all 5 transcripts showed signal alteration during the process of in vitro micro-tubers formation. The sequences appeared to be highly homologous with 60S ribosomal protein, 26S ribosomal RNA gene, zinc transporter protein, 12kD storage protein and malate dehydrogenase, respectively. These results would facilitate the functional characterization of the GA-related genes associated with in vitro micro-tubers development and subsequent in vitro manipulation.

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