Study On Flavonoid Synthesis Regulated By Tartary Buckwheat M~6A Methyltransferase FtFIP37 In Response To Drought Stress

Tartary buckwheat(Fagopyrum tataricum)is a small crop rich in biological flavonoids such as rutin,anthocyanin and quercetin.Flavonoids are a class of secondary metabolites in plants,which can eliminate the excessive reactive oxygen after abiotic stress,and flavonoids improve plant adaptation to environmental changes.Drought,as one of the main abiotic stresses,seriously affects the yield and quality of crops.Tartary buckwheat itself has high cold and drought resistance.Exploring the drought resistance mechanism of Tartary buckwheat and increasing the content of flavonoids is of great significance in cultivating new buckwheat varieties with high yield,high nutritional value,and water-saving drought resistance.This study used Tartary buckwheat as the material.The drought resistance of different buckwheat varieties was analyzed through drought stress experiments,bioinformatics analysis,physiological and biochemical experiments;The m~6A methyltransferase related genes have been cloned and identified in Tartary buckwheat;The module of Ft FIP37-Ft MYB15-Ft PAL1 has been obtained,which it regulates flavonoid synthesis during drought;The mechanism of Ft FIP37 and Ft MYB15regulating the synthesis of flavonoids in Tartary buckwheat in response to drought stress was explored.The main results are as follows:(1)Dingku 1 has strong drought resistance.By analyzing the physiological indicators of stress resistance and changes in flavonoid content,the tolerance differences of different varieties of Tartary buckwheat to drought stress were compared,and it was found that Dingku 1 has strong drought resistance;The results also indicate that the overall m~6A modification level and flavonoid content in Tartary buckwheat are correlated with its drought resistance.(2)Ft FIP37 promotes the accumulation of flavonoids and it is responding to drought stress.We have cloned and characterized the m~6A methyltransferase,demethyltransferase,and related genes of flavonoid synthesis pathway in Dingku 1.Evolutionary analysis showed that the m~6A modified gene is highly conserved and has tissue expression specificity;Subcellular localization analysis showed they are in the nucleus;The results of q RT-PCR and flavonoid quantification showed that drought stress significantly induced the expression of Ft FIP37-1 and promoted the accumulation of flavonoids.(3)We have discovered and validated the Ft FIP37-Ft MYB15-Ft PAL1 interaction module and its regulatory mechanism for flavonoid synthesis.The heterologous transformation of Arabidopsis and homologous transformation of Tartary buckwheat hairy roots further demonstrated that both Ft FIP37 and Ft MYB15 can regulate flavonoid synthesis in response to drought stress.In summary,we have selected Dingku 1 as the research material,cloned and characterized m~6A methyltransferase Ft FIP37,transcription factor Ft MYB15,multiple flavonoid synthase Ft Ft PAL1,Ft ANS,and Ft F3H in Tartary buckwheat,and proposed an interaction module for Ft FIP37-Ft MYB15-Ft Ft PAL1.We have explored the mechanism of Ft FIP37 regulating flavonoid synthesis under drought stress,providing a new theoretical perspective and candidate genes for buckwheat breeding,and laying the foundation for the study of RNA methylation in buckwheat breeding.