[Cloning, Characterization and Expression Vector Construction of Potato Proteas-inhibitor II Gene (PIN II-2x) from Diploid Potato (Solanum phurejia).].

Based on the published gene sequence of tetraploid potato (Solanum.tuberosum) protease-inhibitor II, a genomic DNA and a cDNA sequence of potato protease-inhibitor II gene were obtained from the cDNA library and the genomic DNA of a diploid potato IVP101 (Solanum.phurejia) using PCR method and named PINII-2x. Nucleotide sequencing confirmed that the full-length DNA of PINII-2x was 580 bp, including an 115 bp intron and two exons. cDNA was 462 bp ( stop codon TGA not included) and had 88% similarity to the tetraploid potato protease-inhibitor II. The PINII-2x open reading frame encodes a 154-amino acid polypeptide with a predicated size of 16.6 KD and a calculated PI of 6.08. The deduced proteins from PINII-2x cDNA had 93% homology with other tetraploid potato protease-inhibitor II, which contain the intact signal peptide and two active site similar to the potato protease-inhibitor II family. Test of the RT-PCR indicated that PINII-2x mRNA is wound- induced expression in potato leaves. Binary vector of PINII-2x cDNA drove by either rice Actin I promoter (ActI) or maize Ubiquitin promoter (Ubi) was constructed.