Abstract: Pugionium dolabratum LIPID TRANSFER PROTEIN 3 (PdLTP3) was cloned from endangered desert plant P. dolabratum. Protparam, Multiple Sequence Alignment, MEGA, SignalP 4.1 Server, TMHMM Server v.2.0, SOPMA, and SWISS-MODEL softwares were performed to analyze the predicted amino acid sequence of PdLTP3 gene. The relative gene expression pattern of PdLTP3 under drought stress was investigated by qPCR. The results suggested that the full length of PdLTP3 gene was cloned from P. dolabratum cDNA, encoding a 116 amino acids protein with a calculated molecular weight of 11.7 kD and a theoretical isoelectric point of 8.91. The grand average of hydropathicity of PdLTP3 was 0.569, representing a hydrophobic protein. The homologous alignment showed the PdLTP3 protein was high similarity with Arabidopsis thaliana LTP3 protein. The sequence of 1-23 amino acids in N terminal of PdLTP3 was signal peptide. The secondary and tertiary structure prediction showed that the PdLTP3 protein was mainly composed of alpha helix and random coil. Under drought stress, the gene expression of PdLTP3 was increased gradually and the expression level after 5 hours treatment increased to 48.6 times compared that before treatment, suggesting PdLTP3 probably involves in drought tolerance. These results provide a basis for further study of the function of PdLTP3 and the drought tolerance mechanism of P. dolabratum.

Key words: lipid transfer protein, Pugionium dolabratum, bioinformatics analysis, drought stress, gene expression