景宁木兰TCP家族鉴定及遮阴胁迫表达模式分析

Identification of TCP Family in Magnolia sinostellata and Expression Patterns of TCPs Under Shading Stress

摘要:

为明确TCP转录因子家族在景宁木兰(Magnolia sinostellata)遮阴胁迫中的作用，通过模拟自然生境对景宁木兰3 a生嫁接苗进行遮阴处理，基于转录组分析TCP转录因子相关信息，利用转录组表达量和qRT-PCR分析遮阴胁迫下的表达模式。结果表明，从景宁木兰转录组中筛选出12个TCPs基因，编码蛋白长度为228~558个氨基酸，分子量为23.7~52.7 kDa，TCPs蛋白均为不稳定蛋白、亲水性蛋白；TCPs均定位于细胞核，MsTCP20-a/b蛋白还定位于叶绿体。TCPs成员分为2大类，Class Ⅰ包含10个TCPs成员，Class Ⅱ包含2个TCPs成员。所有成员均含有TCP保守结构域，亲缘关系较近的成员具有相似的保守基序；克隆得到TCPs启动子序列，其序列含有大量光响应和激素响应元件。在遮阴处理后景宁木兰TCPs基因存在差异表达，其中MsTCP9-a与MsTCP2在遮阴后显著上升，MsTCP8、MsTCP9-b、MsTCP7-a、MsTCP15在遮阴后显著下降。因此，景宁木兰TCPs可能在响应遮阴胁迫过程中发挥重要功能。

关键词:TCP转录因子家族;景宁木兰;遮阴;基因表达

Abstract:

In order to investigate the role of TCP transcription factors family of 3-year-old Magnolia sinostellata grafted seedlings under simulated natural shading, the bioinformation of TCP transcription factors were analyzed based on transcriptome data, as well as their expression patterns under shading stress. The results showed that 12 TCPs were identified from the transcriptome data of M. sinostellata, encoding 228-558 amino acids with protein size of 23.7-52.7 kDa. All of 12 TCPs proteins were unstable and hydrophilic. The 12 TCPs located in cell nucleus, and MsTCP12-a/b also located in chloroplast. MsTCPs could be divided into two types, Class I contained 10 TCP members, and Class II with two TCP members. All members contained TCP conserved domains and the closely TCP members had similar conserved motifs. Meanwhile, the TCP promoter sequences of M. sinostellata were cloned and analyzed, which contained a large number of light response elements and hormone response elements. The MsTCPs were differentially expressed under shading treatment. MsTCP9-a, MsTCP2 were significantly up-regulated and MsTCP8, MsTCP9-b, MsTCP7-a, MsTCP15 were significantly down-regulated. Therefore, MsTCPs might play an important role in response to shade stress.

Key words:TCP transcription factor family;Magnolia sinostellata;Shading;Gene expression