The Effect Of Light Intensity On Safflower Quality And Preliminary Study Of Its Mechanism

Safflower is a commonly used traditional Chinese medicine to promote blood circulation,and there is a significant geographical difference between the main producing areas with historical producing areas in China.The influence of the change of producing areas on safflower quality is not clear.The subject group based on the Maxent model and ArcGis system found that light was the main ecological factor affecting safflower growth.Firstly,this reserch preliminarily investigated the origin of safflower and changes in the producing areas.Secondly,the the effect of light intensity on safflower color and main active constituents were analyzed.Nextly,transcript of flower cultivated in different light conditions were measured by RNA-seq.Finally,the effects of different light intensity on safflower quality,especially on flavonoids biosynthesis,were investigated by excavating differently expressed genes.Through the development of this study,the effect of light intensity on safflower quality and its molecular mechanism were analyzed preliminarily.The main results of the study are as follows.1.The study concludes that the origin of safflower was considered as the Fertile Crescent in reasonably.The change of producing areas in China were affected by more suitable natural environment,as well as population,agriculture,economy and many other social factors.2.In the flowering period of safflower,three different light intensities were used to cultivate,and the main characters of safflower under various conditions were recorded.The main active constituents of safflower were determined by HPLC.The results showed that the color of safflower powder was more bright and yellow in decreasing light intensity,and the content of hydroxysafflower yellow A and kaempferol were increased obviously when light intensity decreased.3.The RNA-seq was used to determine the blooming safflower under three different light intensities.The sequencing measured 82.01 Gb data,assembled and redundant to get 129,544 Unigene,commented on to seven functional databases,and eventually 78,179 Unigene obtained functional annotations and 1938 differently expressed genes were founded.4.Seven differently expressed genes which related with flavonoids biosynthesis were named as CtHCT1,CtHCT2,CtHCT3,CtFLS1,CtFLS2,CtANS1,CtANS2.The expression of differently expressed genes were analyzed by RT-PCR.The results showed that CtHCT1,CtHCT2,CtFLS1 and CtANS1 were down regulated in low light intensity,CtHCT3 was down regulated in middle light intensity,and CtFLS2 and CtANS2 was up regulated in low light intensity.The results of expression analysis were in agreement with the RNA-seq.The analysis of correlations among the main active constituents,color of flowers and expressions of seven genes showed that the more “bright and yellow” the color was,the higher hydroxysafflower yellow A content was.There was a significant negative correlation between the expression of CtHCT3 and kaempferol content.The results of this study showed that the decrease of light intensity within a certain range would decrease the expression of HCT gene in safflower,and low expression of HCT would inhibit the growth of the plant and promote the accumulation of flavonoids.That to say,the strong light would increase the production of safflower,but the suitable weak light could promote the accumulation of the active constituents in safflower.