摘要： 为研究旱生植物中醛脱羰基酶基因（ECERIFERUM1，CER1）在响应渗透胁迫过程中的分子特性，用逆转录PCR（Reverse transcription PCR，RT-PCR）和RACE法克隆了耐盐耐旱的扁果枸杞CER1基因的cDNA序列，对该序列进行了生物信息学分析，并用实时荧光定量PCR（Quantitative Real-time PCR，qRT-PCR）法检测在渗透胁迫处理后扁果枸杞CER1在各器官中的转录水平。结果表明，扁果枸杞CER1的cDNA序列长2 168 bp，开放阅读框为1 881 bp，命名为LbCER1，编码626个氨基酸，有4个跨膜区、1个脂肪酸羟化酶结构域和1个位于C-末端的Wax2结构域。该蛋白的理论分子质量为72.47 ku，等电点为7.40，脂肪指数为91.28，不稳定系数为27.88，平均亲水性为-0.070，是一种耐高温、性质稳定的偏碱性亲水蛋白。LbCER1蛋白定位在内质网膜上，二级结构主要由α-螺旋和环组成，分别占44.09%和45.21%，与三级结构预测结果相符。LbCER1与茄科植物亲缘关系近，同源性达100%。LbCER1基因在叶、茎、根中均表达。与对照相比，160 mmol/L山梨醇渗透胁迫处理下，6 h时LbCER1基因在叶中的相对表达量最高，增加1.8倍，茎中的相对表达量增加21%，12 h时降低14%，根中渗透胁迫处理6，12 h时，LbCER1的相对表达量分别增加1.1倍和32%；80 mmol/L山梨醇渗透胁迫下，仅叶在处理6 h时LbCER1表达量增加66%，茎和根中表达量降低或差异不显著，表明LbCER1可能与扁果枸杞响应渗透胁迫有关。

关键词: 扁果枸杞, LbCER1基因, 克隆, 基因表达

Abstract: In order to identify the molecular characterization of fatty-aldehyde decarboxylase gene (ECERIFERUM1, CER1) involved in osmotic stress of xerophyte, CER1 gene was cloned from the cDNA of Lycium barbarum ssp. Bianguo by reverse transcription PCR (RT-PCR) and RACE method, which was a kind of salt-tolerant and drought-tolerant plant. Then the sequence was analyzed by bioinformatics software. Furthermore, the gene expression level of CER1 in L. barbarum ssp. Bianguo was detected in leaf, stem and root under osmotic stress treatment by quantitative Real-time PCR (qRT-PCR). The results showed that the gene sequence of CER1 in L.barbarum ssp. Bianguo contained 2 168 bp in full length and an open reading frame of 1 881 bp, which was named LbCER1, encoding 626 amino acids. Based on bioinformatics analysis, the protein contained four transmembrane regions, a fatty acid hydroxylase domain and a Wax2 domain of C-terminal. The calculated molecular weight, isoelectric point, aliphatic index, instability index and average hydropathicity (GRAV) of LbCER1 was 72.47 ku, 7.40, 91.28, 27.88 and -0.070, respectively. LbCER1 is a stable hydropathic protein possessing alkalinity and high-temperature tolerance, which is located in the membrane of plastic reticulum. Based on the secondary structure prediction of LbCER1, the majority of its amino acid compose alpha-helix (44.09%) and loop (45.21%), which was confirmed by tertiary structure prediction. In addition, LbCER1 was predicted to have 100% homologous with Solanaceae CER1 by phylogenetic analysis. Expression pattern of LbCER1 showed that it express in roots, stems, and leaves. The LbCER1 was also induced by 160 mmol/L sorbitol for 6 h in leaf, stem, and root to 1.8, 1.2, and 1.1 fold, respectively. On contrary, LbCER1 was only sensitive to 80 mmol/L sorbitol in leaves after 6 h-treatment. These results indicate that LbCER1 may play a role in osmotic stress response in L. barbarum ssp. Bianguo.

Key words: Lycium barbarum ssp. Bianguo, LbCER1 gene, Cloning, Gene expression

中图分类号: 

• S567.03

• Q78