中文摘要：

以毛白杨为材料，结合生物信息学和分子生物学技术，利用现有的杨树基因组EST序列库资源，通过同源序列搜索，经过多次拼接合并，获得了理论的杨树油酸去饱和酶基因PtFAD2 cDNA序列；首次利用RT-PCR方法从杨树这个物种中成功克隆得到毛白杨PtFAD2全长编码序列cDNA（GenBank注册号：DQ316788），该cDNA长1276bp，开放阅读框编码388个氨基酸。RT-PCR半定量研究表明：PtFAD2在叶片、茎、根不同组织中的表达量基本一致，并且在4℃低温处理过程中转录表达量没有变化，说明短时间内该基因表达不受低温诱导。

英文摘要：

The endoplasmic reticulum 18：1 fatty acid desaturase （FAD2） is to provide 18：2 fatty acid required for the correct assembly of cellular membranes throughout the plant. In this study, a full-length cDNA clone of PtFAD2 gene （GenBank accession number： DQ316788） was firstly isolated using the in silico cloning method in Populus tomentosa. It is 1 276 bp in length and the open reading frame encodes a peptide of 388 amino acids, which match the known peptide sequences. The predicted amino acid sequence shows significant homology with those of other plant species, which contain typical domains owned by FAD2 proteins. The transcripts of PtFAD2 are equal in leaves, stem and roots using semi-quantitative RT-PCR. When the shoots were experienced the cold treatments, the transcripts of PtFAD2 isn＇t reduced in 24 h. This suggests that the PtFAD2 may be a structural expression protein and it isn＇t induced by low temperature. This study provides the basis for not only cloning and research of poplar fatty acid desaturase gene, but also the genetic engineering of plant fatty acid in the near future.