关键词: 马铃薯, L–抗坏血酸, L–半乳糖酸–1, 4–内酯脱氢酶, 克隆, 基因表达

Abstract: A full-length cDNA clone encoding L-galactono-1，4-lactone dehydrogenase（GLDH），named as StGLDH（GenBank：FJ755844），was isolated from the leaf of potato（Solanum tuberosum L.）cv. Favorita by RT-PCR，nested PCR and RACE. StGLDH transcript is 2 563 bp long with an open reading frame of 1 773 bp and encodes a polypeptide of 590 amino acids. Sequence analysis showed that deduced StGLDH protein was highly homologous to other GLDH proteins from different species，especially with Solanum lycopersicum，Capsicum annuum，Nicotiana tabacum，about 90.6%–95.9% identity in amino acid sequence．Real time PCR analysis indicated that StGLDH expressed in different organs. The transcription level of StGLDH in mature leaves and young leaves were higher than that in old leaves，stems，roots and tubers respectively. The ascorbic acid content was positively related to the StGLDH transcription level in all organs except the ascorbic acid content in stolon. 　

Key words: Solanum tuberosum L., ascorbic acid, L-galactono-1, 4-lactone dehydrogenase（GLDH）, cloning, gene expression