Mechanism Of Cool Temperature Regulating Growth And Main Metabolites Biosynthesis In Angelica Sinensis

Angelica sinensis,a perennial herb that produces ferulic acid and phthalides for the treatment of cardio-cerebrovascular diseases,prefers growing at an altitude of 1800~3000 m.Geographical models have predicted that high altitude,cool temperature and sunshade play determining roles in geo-authentic formation.Although the roles of altitude and light in yield and quality have been investigated,the role of temperature in regulating growth,metabolites biosynthesis and gene expression is still unclear.Based on this,this study explored the effects of cool temperature on the growth of A.sinensis and the mechanism of biosynthesis of active substances.OBJECTIVE: To explore the effects of different temperatures(8℃,15℃,22℃and 30℃)on the growth,metabolite biosynthesis and related gene expression of A.sinensis,and to reveal the response mechanism growth and biosynthesis of A.sinensis to cool temperature,so as to lay a theoretical foundation for improving the yield and quality of A.sinensis.METHODS: In this study,A.sinensis seedlings were treated with cool temperature(8℃,15℃),normal temperature(22℃)and high temperature(30℃)to observe the growth states under different temperatures.The physiological characteristics(plant height,root lengthstem diameter,root diameter,fresh weight and dry weight,etc.),metabolites(ferulic acid,ligustilide,soluble sugar,total flavonoids and total phenols)and antioxidant capacity(DPPH and FRAP)of A.sinensis were determined under different temperatures.q RT-PCR was used to verify A.sinensis at different temperatures,and the expression levels of related genes were determined.RESULTS:1.The biomass of A.sinensis increased at 15℃compared to 22℃.Compared with 22℃,the plant height of seedlings under 15℃was 2.57 cm lower than that under 22℃,and the root length had no significant difference,but the other characteristicswere increased from1.10-to1.15-fold.2.The metabolites and antioxidant capacity of A.sinensis increased at 15℃compared to 22℃;the content of ligustilide in plants was not significantly different at 15℃,but the contents of other metabolites(ferulic acid,soluble sugar,total flavonoids,total phenols)were increased from 1.19-to 1.90-fold.The antioxidant capacity was also significantly enhanced.3.The expression levels of biosynthesis-related genes in A.sinensis at different temperatures were different;The expression levels of genes related to ferulic acid biosynthesis(PAL1,4CLL4,4CLL9,C3 H,HCT,CCOAMT and CCR)and genes related to flavonoid biosynthesis(CHS and CHI)increased from 2.50-to 11.48-fold at 15℃compared to 22℃.Other genes related to polysaccharide biosynthesis and volatile oil biosynthesis were also differentially expressed at different temperatures.CONCLUSION: A.sinensis could not grow at higher temperature(30℃),and was more suitable for growing at cool temperature(15℃).Cool temperature can promote the growth of plants,promote the accumulation of ferulic acid,flavonoids and other metabolites;Biosynthesis of ferulic acid may depend on the CCOAMT pathway rather than the COMT pathway,depending on gene expression levels.These findings authenticate that cool temperature plays a determining role in the formation of geo-authentic and also provide a strong foundation for regulating metabolites production of A.sinensis.