Objective: The exogenous gibberellin(GA) and ethylene(ET) treatment can improve the medicinal ingredients of Salvia miltiorrhiza. Interestingly, many reports pointed out that WRKY transcription factors played an important regulatory role in these treatment responses. However, whether the Sm WRKY mediate these treatment signalings in S. miltiorrhiza remains largely elusive.Methods: qRT-PCR was used for SmWRKY42-like in response to exogenous GA and ethephon(Eth) treatment. The subcellular location of SmWRKY42-like was transiently transformed into onion epidermal cells by particle bombardment. The self-activating activity of SmWRKY42-like was verified in AH109 yeast strain.Results: Sm WRKY42-like was a WRKY family gene in S. miltiorrhiza. The subcellular localization and transcriptional activity results of the SmWRKY42-like protein indicated that SmWRKY42-like mainly enriched in nucleus and might be a transcription factor in S. miltiorrhiza. In the meantime, the SmWRKY42-like gene significantly responded to exogenous GA and Eth treatment.Conclusion: These results collectively indicated the SmWRKY42-like gene functions, as an important hormone-responsive gene, might play a potentially role in ET and GA signaling pathways.
Salvia miltiorrhiza, a popular traditional Chinese medicine, is widely used for treatments in cardiotonic disease. Tanshinones are a group of bioactive ingredients in S. miltiorrhiza. In this study, Ce^3＋ was used as an elicitor to enhance tanshinones production in S. miltiorrhiza hairy roots. The results showed that contents of dihydrotanshinone I（DTI） and cryptotanshinone（CT） were significantly enhanced by 50 μmol/L Ce^3＋, and reached to 0.875 mg/g and 0.271 mg/g, respectively. However, tanshinone II A（TIIA） and tanshinone I（TI） contents were significantly decreased to 59% and 62% of the control. Simultaneously, expressions of genes（HMGR, DXR, DXS1, DXS2 and GGPPS） involved in tanshinone biosynthesis were upregulated by Ce^3＋. Responses of DXS1, DXS2 and GGPPS to Ce^3＋ treatments were later than HMGR and DXR. We speculated that branch pathways of DTI and CT biosynthesis were probably different from TIIA and TI. This work will help us understand biosynthetic mechanism of tanshinones in plants.
