外源激素诱导黄芩愈伤组织形成关键基因初筛

Preliminary screening of key genes for callus formation induced by exogenous hormones in Scutellaria baicalensis

关键词:  黄芩，愈伤组织，酶活性，转录组，激素信号转导途径

Key words:  S. baicalensis Georgi, Callus, Enzyme activity, Transcriptome, Hormone signal transduction pathway

摘要:

黄芩（Scutellaria baicalensis Georgi）为唇形科黄芩属多年生草本植物，其体内富含多种活性成分，具有广泛的药理活性及较高的药用价值与开发潜力。为深入解析黄芩愈伤组织形成的分子机制，本研究以黄芩组培苗茎段为外植体，结合高通量转录组测序技术与关键酶活性测定，系统筛选参与调控愈伤组织形成过程的关键基因。结果表明：（1）不同激素组处理黄芩愈伤组织后，植物激素信号转导途径共有33个基因差异表达，利用WGCNA分析筛选到了9个可能在黄芩愈伤形成中响应不同激素信号的关键差异表达基因，即PP2C、JAZ、DELLA、ABF、BRI1、EIN3、ERF1、GID1和MYC2。（2）不同激素组处理黄芩愈伤组织后SOD、POD、CAT、PAL酶均在7~14 d间有最大酶活性，此时愈伤组织增殖迅速，且高分化或者绿色愈伤组织的SOD、POD和CAT酶活性高于黄色愈伤组织。（3）筛选到了与黄芩愈伤组织CAT和POD酶活性相关的2个差异表达基因，即EIN3和DELLA。研究结果为明确黄芩愈伤组织形成的分子机理提供一定的理论依据。

Abstract:

Scutellaria baicalensis Georgi is a perennial herb of the genus Scutellaria in the family Labiatae. It is rich in a variety of active ingredients, and has a wide range of pharmacological activities and high medicinal value and development potential. In order to further analyze the molecular mechanism of callus formation in S. baicalensis, this study relied on the high-throughput sequencing platform and used the stem segments of S. baicalensis tissue culture seedlings as materials to analyze the transcriptome of S. baicalensis explants under different hormones. At the same time, the enzyme activities (SOD, POD, CAT, and PAL) of S. baicalensis callus grown for 7 d, 14 d, and 21 d were determined to screen the key genes related to the formation of S. baicalensis callus. The results showed that: (1) After the callus of S. baicalensis was treated with different hormone groups, there were 33 differentially expressed genes in the plant hormone signal transduction pathway. WGCNA analysis was performed on 18 398 Unigenes identified in the callus of S. baicalensis, and a total of 16 gene modules were obtained. Among them, the gene modules related to the plant hormone signal transduction pathway were blue and brown, and 9 key differentially expressed genes that may respond to different hormone signals in the callus formation of S. baicalensis were screened, namely PP2C, JAZ, DELLA, ABF, BRI1, EIN3, ERF1, GID1, and MYC2. (2) The activities of SOD, POD, CAT, and PAL in different hormone groups were the highest in 7~14 d, and the callus proliferated rapidly. At the same time, the enzyme activities of SOD, POD and CAT in highly differentiated or green callus were higher than those in yellow callus. (3) The correlation analysis between the enzyme activity of the explants and the differentially expressed genes in the plant hormone signal transduction pathway in the control group and the explants treated with different hormones for 7 days, 2 differentially expressed genes related to the CAT and POD enzyme activities of S. baicalensis callus were screened, namely EIN3 and DELLA. The results provide a theoretical basis for clarifying the molecular mechanism of callus formation in S. baicalensis.