《植物生理学报》 2021, 57(2): 439-450
髓细胞组织增生蛋白(MYC2)转录因子属于碱性螺旋-环-螺旋(bHLH)转录因子家族, 可以调控植物萜类次生代谢产物的合成。本研究首次从北柴胡毛状根中成功克隆一条MYC2转录因子全长基因序列, 命名为BcMYC2, 共2 103 bp, 开放阅读框长为2 055 bp, 编码684个氨基酸。生物信息学分析表明其与可可(Theobroma cacao)、蓖麻(Ricinus communis)等MYC2蛋白同源性较高; bHLH转录因子家族的系统进化树显示其与MYC2蛋白家族归为一类。组织特异性表达分析发现, BcMYC2基因在茎、叶中表达量较高, 在根中表达量最低。使用不同浓度的茉莉酸甲酯诱导北柴胡毛状根, 显示BcMYC2受茉莉酸信号调节, 毛状根中柴胡皂苷合成途径的关键酶基因及柴胡皂苷含量有明显提高。本研究为进一步验证BcMYC2转录因子对柴胡皂苷生物合成途径的调控功能奠定基础。
关键词：北柴胡; 转录因子; MYC2; 柴胡皂苷; 茉莉酸甲酯
Corresponding author: LIU Changli; E-mail: email@example.com
The MYC2 transcription factor belongs to the bHLH transcription factor family and can regulate the synthesis of terpene-type secondary metabolites in plants. In this study, the full-length gene sequence
of the MYC2 transcription factor was successfully cloned from the hairy roots of Bupleurum chinense for the frst time. The gene was named BcMYC2 and was found to contain a total of 2 103 bp, with an ORF of 2 081 bp encoding 684 amino acids. Bioinformatics analysis showed that it has high homology with MYC2 proteins from other important plants such as Theobroma cacao and Ricinus communis, and the phylogenetic tree confirmed that it belongs to the MYC2 protein family. Tissue-specific expression analysis revealed that the BcMYC2 gene was expressed at a higher level in stems and leaves, and at the lowest level in roots. The use of exogenous MeJA to induce hairy roots of Bupleurum chinense showed that BcMYC2 is regulated by the jasmonate signal. Moreover, the key enzyme genes of the saikosaponin synthesis pathway and the content of saikosaponin in hairy roots were signifcantly increased by jasmonate induction. This study offers a solid basis for further research on the regulatory function of the BcMYC2 transcription factor in the saikosaponin biosynthetic pathway.
Key words: Bupleurum chinense DC.; transcription factor; MYC2; saikosaponin; methyl jasmonate
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