LED Light And Amino Acids Regulate The Accumulation Of Folate In Wheat Seedlings

Wheat（Triticum aestivum L.）is a monocotyledonous plant of the gramineae family and an important food crop in northern China.After germination,the nutrients were transformed and the content of biologically active ingredients significantly increased.As an important cofactor in the one-carbon transfer reaction,folate（vitamin B9）is essential for cell metabolism.Folate cannot be synthesized in the human body and need to be obtained through diet.Therefore,the use of biotechnology to increase folate content of food raw materials has become a research hotspot.As a signal factor,light affects the growth and development of plants and regulates the transformation and accumulation of a variety of secondary metabolites in plants.A variety of amino acids were involved in the synthesis and regulation of folate.In this study,wheat seedlings were used as test materials,and the effects of LED light and amino acids on the regulation of folate accumulation in wheat seedlings were studied on the synthesis precursors,enzymes and gene expression levels.The main results were as follows:1.The effects of LED light spectrums on the main physiological and biochemical metabolism and folate content in wheat seedlings were studied.The results showed that light significantly improved the level of endogenous hormones in wheat seedlings.Red light and white light were more conducive to chlorophyll accumulation,red light and yellow light promote wheat seedlings elongation and increased fresh weight.Each light spectrum promoted soluble sugar and soluble protein accumulation,yellow light was more conducive to the accumulation of amino acids.Blue light,green light and yellow light significantly increased the total phenolics and phenolic acid content of wheat seedlings,and improved the DPPH·and ABTS⁺·scavenging ability of wheat seedlings.Ferulic acid,p-coumaric acid and caffeic acid were significantly increased under blue,green and yellow light treatments.Red light has a better effect of enriching folate,which significantly increased the synthesis of THF and 5-CH₃-THF of wheat seedlings,thereby increasing the level of total folate.2.The effects of red light on the folate synthesis precursors,key enzyme activities and gene expression in wheat seedlings were studied.The results showed that the 30μmol·m^-2·s^-1of red light treatment was most conducive to the accumulation of folate in wheat seedlings,and the folate content increased by 23.87%compared with the control.Folate content in the leaves of wheat seedlings was higher compared with endosperm and roots.The content of 5-CH₃-THF was the most abundant in leaves,which was significantly increased under red light treatment,thereby increasing the total folate level of wheat seedlings.Red light significantly reduced the total folate content in roots,which mainly due to the decrease of 5-CH₃-THF content.Red light uper-regulated the expression of key folate synthesis genes in leaves-GTPCH1,ADCS,HPPK/DHPS and FPGS,improved the activities of GTP cyclohydrolase 1（GCH1）and aminodeoxychorisate synthase（ADCS）,also increased the content of folate synthesis precursors such as pterin and p-aminobenzoic acid,thereby promoted the synthesis of folate.3.The effects of amino acids on folate content in wheat seedlings were studied.The efficient amino acid culture solution was screened out through orthogonal experiments,and the composition and content of folate under amino acids treatment were analyzed.The content of endogenous amino acid,folate precursors and the expression of key gene on folate accumulation under amino acid treatment were discussed.The results showed that the addition of phenylalanine,tyrosine,tryptophan,glutamic acid and p-aminobenzoic acid significantly increased the total folate content in wheat seedlings.Obtained by the orthogonal experiment of five factors and four levels.When wheat seedlings were cultured with a mixed medium of 1.50 m M phenylalanine,0.50 m M tyrosine,0.50 m M tryptophan,0.75 m M para-aminobenzoic acid and 0.50 m M glutamic acid,the folate accumulation was the highest.The total folate content of wheat seedlings was as high as 417.24μg/100g DW.THF and 5-CH₃-THF content significantly increased after adding amino acids.Phenylalanine and tryptophan treatment uper-regulated ADCS expression,which promoted the synthesis of p ABA.p ABA and glutamate respectively uper-regulated the expression of HPPK/DHPS and FPGS,thereby accelerating the synthesis of folate in the mitochondria.Under the optimal amino acid mixture culture,the expression of GTPCH1,ADCS,HPPK/DHPS and FPGS in the folate synthesis pathway were significantly uper-regulated,the content of folate precursors increased,and thereby folate synthesis increased.