Abstract:

Two pumpkin cultivars for cucumber grafting‘Yunnan Figleaf Gourd’（Cucurbita ficifolia）and‘Huangchenggen 2’（C. moschata），which have weak and strong de-blooming abilities respectively，were used in this study，and the full length cDNA of the silicon transporter gene were cloned by RT-PCR and RACE，and named CmLsi3（GenBank accession numbers are KM203110 and KM359142）. The full-length of cDNA was 1 206 bp，and the open reading frame（ORF）was 795 bp，encoding 264 amino acids，and only four amino acids were different in‘Yunnan Figleaf Gourd’and‘Huangchenggen 2’，However the amino acid sequences shared at least 50% identity with those in cucumber，maize and barley. The transporter encoded by CmLsi3 contained typical two sparagine-proline-alanine（NPA）motifs，six transmembrane domains and a distinct ar/R（aromatic/arginine）selectivity filter composed from Gly（G），Ser（S），Gly（G）and Arg（R），belonging to nodulin 26-like intrinsic membrane protein Ⅲ（NIP Ⅲ）subgroup of plant aquaporin. The expression of Cmlsi3 was investigated by using fluorescence quantitativeRT-PCR and the result showed that the CmLsi3 gene was expressed in roots，stems and leaves of pumpkin and the expression level in organs were higher in‘Yunnan Figleaf Gourd’than in‘Huangchenggen 2’.

Key words: pumpkin, silicon transporter gene, clone, expression analysis