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:  Scutellaria baicalensis, callus, enzyme activity, transcriptome, hormone signal transduction pathway

摘要:

黄芩(Scutellaria baicalensis)是唇形科黄芩属多年生草本植物,因含有多种活性物质而展现出广泛的药理活性,具有较高的药用价值和开发前景。为探究黄芩愈伤组织形成机理,该研究以黄芩组培苗茎段为材料,依托高通量测序平台,采用转录组学测序及酶活性测定的方法,筛选与黄芩愈伤组织形成相关的关键基因。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)除BA-NAA处理组的超氧化物歧化酶(SOD)和BA-2,4-D处理组的过氧化物酶(POD)酶活性在第21天最大以外,其他处理组的SOD、POD、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)均在第7天或第14天时有最大酶活性,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。该研究结果为明确黄芩愈伤组织形成的分子机理提供了一定的理论依据。

Abstract:

Scutellaria baicalensis is a perennial herb of the genus Scutellaria in the family Lamiaceae. It exhibits a wide range of pharmacological activities due to its various active substances, and has high medicinal value and development prospects. In order to explore the formation mechanism of S. baicalensis callus, this study used stem segments of S. baicalensis tissue culture seedlings as materials and employed transcriptome sequencing and enzyme activity determination methods based on a high-throughput sequencing platform to screen key genes related to callus formation in S. baicalensis. The results were as follows:(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. Using WGCNA analysis, nine key differentially expressed genes that may respond to different hormone signals during callus formation in S. baicalensis were screened, namely PP2C, JAZ, DELLA, ABF, BRI1, EIN3, ERF1, GID1, and MYC2.(2)Except for superoxide dismutase(SOD)activity in the BA-NAA treatment group and peroxidase(POD)activity in the BA-2,4-D treatment group reaching their maximum levels on the 21st day, the maximum enzyme activities of SOD, POD, catalase(CAT)and phenylalnine ammonialyase(PAL)in the other treatment groups were observed on the 7th or 14th day, during which the callus proliferated rapidly. Meanwhile, the activities of SOD, POD, and CAT in highly differentiated or green callus were higher than those in yellow callus.(3)Through correlation analysis between explant enzyme activities and differentially expressed genes in the plant hormone signal transduction pathway in the control group and explants treated with different hormones for 7 d, two differentially expressed genes related to CAT and POD enzyme activities in 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.