Abstract: 【Objective】The research aimed to identity the function of Arabidopsis thaliana protein gene AtRHD3（root hair defective 3）in anthocyanin biosynthesis.【Methods】Compared the anthocyanin content induced by sucrose in wild type Col-0 and mutant rhd3 and relative expression of genes in anthocyanin biosynthesis pathway by real-time fluorescent quantitative PCR.【Results】With the increasing content of 5% sucrose,anthocyanin content in wild type Col-0 and mutant rhd3 were increased,and the anthocyanin accumulation in mutant rhd3.It is significantly higher than the wild type Col-0,implied that AtRHD3 played negative role in anthocyanin biosynthesis induced by 5% sucrose.The expression levels of structural genes and regulatory genes of anthocyanin biosynthesis pathway in wild type Col-0 and mutant rhd3 after control and 5% sucrose treatment were analyzed.The results showed that compared with wild type Col-0,the expression levels of structural genes（AtDFR、AtANS、AtUF3GT）and positive regulatory genes（AtPAP1、AtPAP2、AtTT8、AtTTG1）expressed higher level than those in wild type Col-0,while the negative regulator AtMYBL2 expressed lower level.【Conclusion】The study indicated AtRHD3 negatively regulated anthocyanin biosynthesis by affecting the expression levels of structural genes and regulatory genes of anthocyanin biosynthesis pathway in Arabidopsis thaliana induced by sucrose.

Key words: Arabidopsis thaliana, Mutant rhd3, Anthocyanin, Gene expression