黑果枸杞LrTTG1基因的克隆及表达分析

以黑果枸杞为材料，利用RT PCR和RACE技术克隆了花青素合成相关基因LrTTG1（GenBank登录号为MH633481）。序列分析表明，LrTTG1基因cDNA全长1 453 bp，包含1 029 bp开放阅读框，编码342个氨基酸，含有5个WD40重复基序。同源比对结果表明，LrTTG1与茄子SmTTG1的氨基酸序列相似性较高，达到83.73%。qRT PCR分析显示，LrTTG1基因在茎、叶、花、青果、紫果和黑果中均有表达，且在青果中的表达水平（最高）约为黑果（最低）的4倍；紫外胁迫下LrTTG1基因的表达随胁迫时间的延长呈先降低后升高的变化趋势。花青素含量分析表明，黑果的花青素含量最高（11.3 mg/g），分别约为紫果（ 1.2 mg/g）和青果（0.53 mg/g）含量的9.4倍和21.3倍。研究表明，随着黑果枸杞果实的发育，LrTTG1基因的表达量呈现下降趋势，而花青素的含量则呈上升趋势，两者呈负相关关系；推测LrTTG1基因在黑果枸杞花青素合成中可能具有重要的调节作用。

Cloning and Expression Analysis of LrTTG1 from Lycium ruthenicum Murr.

An anthocyanin synthesis related gene named LrTTG1 (GenBank accession number MH633481) was cloned from Lycium ruthenicum using RT PCR and RACE methods. The sequence analysis showed that the length of LrTTG1 gene was 1 453 bp, which contained a 1 029 bp ORF encoding 342 amino acids with five WD40 repeats. Homology amino acid sequences comparison indicated that LrTTG1 had higher similarity with Solanum melongena TTG1 (83.73%). qRT PCR analysis revealed that LrTTG1 gene was expressed in stems, leaves, flowers, green fruits, purple fruits and black fruits, and the expression level (the highest) in green fruits was about 4 times that of black fruits (the lowest). LrTTG1 gene expression showed a trend on firstly falling and then rising with UV irradiation time. Anthocyanin content analysis showed that the content in black fruits was the highest (11.3 mg/g), which were about 9.4 times and 21.3 times of purple fruits (1.2 mg/g) and green fruits (0.53 mg/g), respectively. This study showed that the expression of LrTTG1 gene tended to decrease with the development of fruits, while the content of anthocyanin tended to increase, showing a negative correlation between them. It is speculated that LrTTG1 gene may play an important role in the anthocyanin synthesis of L. ruthenicum.