甜菜色素合成关键基因的克隆及不同光质对其表达的影响

Cloning of Key Genes of Pigment Synthesis in Beet and Effects of Light Type on Their Expression

甜菜色素是红甜菜的次生代谢产物。为了研究这些含氮次生代谢产物合成过程中UDP-葡糖基转移酶基因(UGT)及酪氨酸酶基因(TYR)的功能及对不同光质的响应、表达机制,初步克隆了UGT、TYR基因并进行了相关生物信息学分析,测定其启动子序列。分析表明:UGT、TYR基因启动子序列中共有的主要元件为TATA-box和CAAT-box;调控有机酸的顺式作用元件W-box(TT⁃GACC)和ABRE;光响应元件ACE和G-Box等。由此推测甜菜UGT、TYR基因的表达对不同光质和有机酸类化学调节物质较为敏感。通过红光(RL)、绿光(GL)和蓝光(BL)不同光质处理发现,3种光均会对甜菜幼苗的生长产生抑制作用,RL处理的抑制作用最明显,GL与BL处理的抑制作用无显著差异。在BL处理下,甜菜幼苗色素含量明显上升,UGT和TYR基因的表达量均表现明显上调;在GL处理下,TYR基因的表达量表现明显上调,而UGT基因表现为先下调、后上调的特点;在RL处理下,TYR基因表达量表现为显著上调,而UGT基因表现为先上调后下调,中间平稳,后期上调的特点,甜菜幼苗色素含量明显下降。

Beet pigment is a secondary metabolite of red beet.To study the function of UDP-glucosyltransferase gene(UGT)and tyrosinase gene(TYR)in the synthesis of these nitrogen-containing secondary metabolites and the response and expression mechanism to light type(red,blue and green),both UGT and TYR genes were cloned and analyzed by bioinformatics to determine their promoter sequences.The results showed that the major elements in both UGT and TYR promoter sequences were TATA-box and CAAT-box,W-box(TTGACC)and ABRE were cis-acting elements regulating organic acids,and optical response elements were ACE and G-Box,etc.As a result,the expression of beet UGT and TYR genes was sensitive to different lights and organic acids as chemical regulators.Through different light treatments of red light(RL),green light(GL)and blue light(BL),it was found that all three kinds of light could inhibit the growth of beet seedlings,and of which the inhibition effect of RL treatment was the most obvious,and there was no significant difference between GL and BL treatments.Under BL treatment,the pigment content of beet seedlings increased significantly,and the expression of UGT and TYR genes was significantly up-regulated;under GL treatment,the expression of TYR genes was significantly up-regulated;while the expression of UGT gene was down-regulated first and then up-regulated.Under RL treatment,the expression of TYR gene was up-regulated significantly,while the expression of UGT gene was up-regulated first and then down-regulated,stable in the middle,and up-regulated in the later stage;the pigment content of beet seedlings decreased significantly.