三七绿紫地上茎bHLH、MYB和WD40转录水平的纵向变化及其与花色苷含量的关系

Longitudinal Changes of Transcriptional Levels of bHLH, MYB and WD40 and Their Relationships with Total Anthocyanin Contents in the Green-purple Aerial Stems of Panax notoginseng

【目的】探究三七绿紫地上茎中三七碱性螺旋-环-螺旋蛋白基因(basic helix-loop-helix gene, bHLH)、v-myb骨髓母细胞增多症病毒癌基因同源物基因(v-myb myeloblastosis viral oncogene homolog,MYB)和WD40蛋白基因(WD40 gene, WD40)转录水平的纵向变化及其与总花色苷含量(total anthocyanin content,TAC)的相关性。【方法】将平均高度约为18 cm的一年生三七绿紫地上茎植株的地上茎均分为18个茎段,分别用实时荧光定量PCR (qRT-PCR)和分光光度法检测各茎段中bHLH、MYB和WD40的转录水平以及TAC。【结果】从三七绿紫茎的顶部到基部,三七bHLH、MYB和WD40转录水平的纵向变化大致分别表现为1条"多峰"、"W"形和"W+倒V"形曲线,其最高转录水平分别出现在茎段7、10和7,且三者转录水平在不同茎段间的差异分别到达了显著(P<0.05)、极显著(P<0.01)和极显著(P<0.01)水平;TAC的纵向变化则粗略表现为1条"单峰"曲线,最高TAC出现在茎段8,且TAC在不同茎段间的差异达到了极显著水平;bHLH、MYB和WD40转录水平与TAC之间均呈正相关,其Pearson相关系数规律为MYB>bHLH>WD40。【结论】对于一年生三七绿紫茎花色苷合成而言,3个转录因子基因的差异性贡献为MYB>bHLH>WD40。本研究结果可为三七地上茎花色苷合成转录调控的探究提供参考。

[Purpose]To explore the longitudinal changes of the transcriptional levels of the basic helix-loop-helix gene(bHLH), v-myb myeloblastosis viral oncogene homolog gene(MYB) and WD40 gene(WD40) of Panax notoginseng and their correlations with the total anthocyanin contents(TACs)in the green purple aerial stems of P. notoginseng.[Methods]The stems of the green purple aerial stemmed plants with an average height of about 18 cm of the one-year-old P. notoginseng were evenly divided into 18 segments. The transcriptional levels of the bHLH, MYB and WD40 and the TACs were determined by using quantitative real-time PCR(qRT-PCR) and spectrophotometry, respectively.[Results]From the tops to the bases of the green purple stems of P. notoginseng, the longitudinal changes of the transcriptional levels of the bHLH, MYB and WD40 of P. notoginseng roughly displayed a "muti-peaked", "W-shape" and "W+inversed V-shape" curves, respectively, the highest transcriptional levels of the three transcription factor genes(TFs) appeared at the segment 7,10 and 7, respectively, and the differences of the levels of the three TFs among the different segments reached the significant, extremely significant and extremely significant levels, respectively. Whereas,the longitudinal changes of the TACs exhibited a "single peaked" curve as a whole, the highest TAC emerged at the segment 8, and the differences of the TACs among the different segments reached the extremely significant level. The transcriptional levels of the three TFs were all positively correlated with the TACs, the corresponding correlation coefficients were as: MYB>bHLH>WD40.[ Conclusions]For the anthocyanin synthesis in the green purple stems of the one-year-old P.notoginseng, the differential contributions of the three TFs were as: MYB>bHLH>WD40.This study could provide a reference for the investigations of the transcriptional regulation of the anthocyanin synthesis in the aerial stems of P. notoginseng.