Effects Of Drought Stress On The Synthesis And Accumulation Of Tanshinones In Salvia Miltiorrhiza Root

Objective: To explore the regulation mechanism of moderate drought stress on the accumulation of tanshinone active ingredients,to reveal the abscisic acid-mediated changes in the biosynthesis of tanshinone active ingredients in response to moderate drought stress from the transcription and metabolic levels,and to clarify the activity of tanshinones on tanshinones.The regulation and control of component biosynthesis provides a theoretical basis for formulating reasonable irrigation measures and innovating excellent germplasm in production.Methods: Through the pot water control experiment,different levels of drought stress treatment groups were set to control the soil water content to be 75%(75% θf),65%(65% θf),55%(55% θf),45 %(45% θf);Using high-performance liquid phase,mass spectrometry imaging,liquid-mass spectrometry and other techniques to analyze the content of tanshinones and endogenous hormones in the roots of Salvia miltiorrhiza plants under different drought stress treatments;10% PEG,200 μM abscisic acid,and abscission,respectively Treatment of hairy roots of S.miltiorrhiza with the acid synthesis inhibitor fluazinon,comparing the contents of four tanshinones including dihydrotanshinone Ⅰ,cryptotanshinone,tanshinone Ⅰ and tanshinone ⅡA,it was clear that abscisic acid regulated the biosynthesis of tanshinones under drought Role;Using second-generation transcriptome sequencing technology combined with q RT-PCR to analyze the difference in gene expression profiles of S.miltiorrhiza plant roots under different drought stress conditions,screen key genes with potential biological functions that regulate the biosynthesis of tanshinone components in response to drought stress,and reveal drought Regulation mechanism of stress on biosynthesis of tanshinone components.Results:(1)The content of four tanshinones and tanshinone ⅡA,tanshinone Ⅰ,tanshinone ⅡA and tanshinone ⅡA in the roots of S.miltiorrhiza plant increased gradually with the increase of drought stress.The ABA content is the highest.The contents of dihydrotanshinone Ⅰ,cryptotanshinone,tanshinone Ⅰ,and tanshinoneⅡA were 21.95 mg / g,52.47 mg / g,13.96 mg / g,and 161.26 mg / g,respectively,which were 2.89 times,2.68 times,2.39 times,and higher than the control 2.04 times;ABA content reached 10.81 ng / g,an increase of 8.38 times compared with the control.(2)After treating the hairy roots of S.miltiorrhizae with abscisic acid and PEG,the four tanshinone components were significantly improved compared with the control,but when treated with flucidone,an abscisic acid synthesis inhibitor,the four tanshinone components were significantly reduced.(3)Transcriptome analysis of S.miltiorrhiza root after drought stress showed that there was one protein kinase closely related to the expression of key enzyme gene for biosynthesis of tanshinone components under drought stress.This gene has high homology with Arabidopsis Sn RK2.8 and is named It was SmSnRK2.8,which was significantly up-regulated by drought stress and induced by abscisic acid.Conclusion: Drought stress promotes the accumulation of tanshinones by phytohormone abscisic acid.SmSnRK2.8 is closely related to the expression of key synthase genes that mediate drought regulation of tanshinones accumulation,and may be the key genes for drought and abscisic acid to regulate the synthesis of tanshinones.