Cloning Of Key Genes Of Betacyanin And Their Expression Under Different Conditions

Betalain is a natural plant pigment which is present in edible red beets.It has good coloring properties for food.What's more,betalain has important edible and medicinal value.Betaine includes betaxanthin and betacyanin,in which the biosynthesis of betacyanin is complex.At present,Most of the research on betaxanthin is about the physiological activity,while its specific biosynthetic pathway is still under study.Over the years,the academic community has been always speculating that glycosyltransferase,tyrosinase are involved in the betalain synthesis pathway,but the molecular biology evidence is not enough.In order to study the expression regulating mechanism of glycosyltransferase gene(UDP gene)and the tyrosinase gene(TYR gene)during the process of betalain metabolism,the two genes were cloned first and their bioinformatics analysis were carried out to obtain the information of theirs encoding protein.Primers were designed according to the cloned genes.The promoter sequences of UDP and TYR genes were obtained by chromosome walking technique.The promoters were analyzed by online software plantCARE.According to the analyze results of promoter sequence,it is speculated that the expression of UDP and TYR genes is sensitive to light and various hormonal chemicals in beet.In order to study the effects of chemical substances and light on the growth of beet and the expression of UDP and TYR genes,the beet seedlings were cultivated under different treatment conditions.The beet seedlings were treated with different allelochemicals which are extracted from soy,corn,cichorium intybus,okra,beet respectively.What's more,the germination experiment about beet was carried out with different allelochemicals.In the light treatment,the beet seedlings were cultivated under red,blue,greenlight respectively.In the germination experiment,five kinds of allelochemicals had different effects on the germination of beet.The results showed that the allelopathic substances of beet and cichorium intybus inhibited the germination of beet seeds.Soybean,okra and corn allelochemicals showed promotion effects.Okra,corn,soybean allelochemicals has a catalytic effect on the seedling fresh weight,plant height,cichorium intybus,beet allelopathy showed inhibition effects.In addition,p-hydroxycinnamic acid in soybeanallelochemicals reduced the synthesis of beet pigments by inhibiting tyrosinase activity,and the other four allelochemicals promoted the content of beet seedlings.The key role of tyrosinase in beet pigment synthesis was confirmed.Different crops have different effects on the expression of sugar beet genes due to the different types of specific allelochemicals.Under different light treatments,green light,blue light and red light all inhibited the growth of seedlings,and the red light was the most obvious.The inhibition of green and blue light was not very different.In addition,under the treatment of different lights,the trend of pigment content increased first and then decreased.Blue light promoted the accumulation of pigment,indicating that short wavelength is conducive to pigment synthesis.Under the three light irradiation,TYR gene expression was almost always up,indicating that monochromatic light can effectively stimulate the expression of TYR gene.The relationship between gene expression level and the accumulation of betalain in beet were studied by cultivating beet seedlings under different allelopathic substances and light.It provided the molecular theoretical basis for the synthesis study of betalain.