Abstract:

In order to improve the accumulation of steroidal glycoalkaloids（SGAs） in the aerial part of potato cultivar and thus to enhance its resistance and tuber quality improvement，the solanidine rhamnosyltransferase（sgt3）gene and ribulose-1,5-bisphoshate carboxylase（Ruisco）promoter were cloned in this research. Subcellular localization prediction showed that SGT3protein did not contain chloroplast transit peptide，mitochondrial peptide and signal peptide sequence. Therefore，we speculated that SGT3 protein was located in the cytoplasm. Furthermore，cDNA fragment of sgt3 and rbcS promoter was recombinated into plasmid pCEPSP. And we got a plant vector with glyphosate resistance marker that has sgt3 gene driven by a green-tissue promoter rbcS（rbcS：sgt3）. In addition，Longshu 3 and Shepody were  transformed by Agrobacterium-mediated protocol，and we obtained 12 glyphosate-tolerant transgenic plantlets. The analysis of gene expression levels indicated that the relative expression of sgt3 transcript in transformation plantlets were higher（1.3–3.0 times）than non-transformation plantlets. Also，the content of SGAs has increased by 20% to 37% for all transformation plantlets. Whereas，SGAs content did not display a significant difference between transgenic tuber and non-transgenic tuber in potato. Our result of this study will provide a theoretical basis for breeding varieties with SGAs content enriched in the foliage but diminished in the tuber in the further.

Key words: Solanum teberosum, steroidal glycoalkaloids, green tissue specific promoter, solanidine rhamnosyltransferase, genetic transformation