以濒危荒漠植物斧翅沙芥（Pugionium dolabratum）为对象，克隆脂质转运蛋白基因PdLTP3。运用Protparam、Multiple Sequence Alignment、MEGA、SignalP 4.1 Server、TMHMM Server v.2.0、SOPMA、SWISS-MODEL等软件对其编码的氨基酸序列进行生物信息学分析，并检测干旱胁迫下PdLTP3基因的诱导表达情况。结果表明：从斧翅沙芥cDNA中克隆到PdLTP3基因全长，开放阅读框编码116个氨基酸，预测分子量为11.7 kD，理论等电点8.91，平均亲水性系数0.569，是一个疏水蛋白质；同源比对显示其编码的蛋白质与拟南芥AtLTP3相似度较高；PdLTP3蛋白N端1~23个氨基酸序列为信号肽序列；二级和三级结构显示PdLTP3蛋白主要由α螺旋和无规则卷曲组成；干旱胁迫下PdLTP3基因表达量逐渐升高，5 h后表达量约为胁迫处理前的48.6倍，说明其可能参与了斧翅沙芥干旱胁迫耐受。
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.
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