Cloning, Expression and Characterization of a Non-Specific Lipid Transfer Protein Gene from Potato

Abstract

Plant non-specific lipid transfer proteins(nsLTPs) are abundantlipid binding proteins with small molecules that play several biological roles including antimicrobial defense,signaling,cell wall loosening,proteinase inhibiting and so on. A new cDNA clone,named StLTPa1,corresponding to potato nsLTP gene was isolated from a cultivated potato(Solanum tuberosum) infected with Ralstonia solanacearum. The sequence analysis showed that the cloned cDNA contained 636 bp nucleotide which encoded a type I nsLTP of 91 amino acids. The StLTPa1 gene is well conserved in the coding region with 60–92% identity at the amino acid level,and 75–85% identity at the nucleotide sequence level compared with other Solanaceae nsLTPs. The transcripts of the gene accumulated in potato leaf and stem tissues induced by R. solanacearum and showed dominant differential expression between resistant and susceptible genotypes. In situ hybridization results showed that the StLTPa1 mRNA was localized in phloem cells of vascular tissues in potato leaf and stem tissues after pathogen infection. Salicylic acid,methyl jasmonate and abscisic acid induced StLTPa1 gene expression in different manners. These three signal molecules could produce a long-term effect on the StLTPa1 gene expression during the early stages of potato—R. solanacearum interaction. These results thus showed that the StLTPa1 may be pathogen-responsive gene in plant defenses and involve in a complex gene regulation network.