Analysis Of Sulcotrione Resistance Of Arabidopsis Glycosyltransferase Gene UGT91C1

With the development of modern agriculture,herbicides are becoming more and more widely used and also bring increasing challenges to crop growth and environmental preservation.Due to the specificity of their own metabolism,some plants can reduce or eliminate the damage caused by herbicides and gain herbicide resistance,which is an important theoretical basis for the research of herbicide-resistant plants at this stage.How to respond to the selective toxicity of herbicides and to maximize the herbicidal benefits have become the most concerned issues.The glycosyltransferases that commonly exist in plant kingdom modify the receptor molecules to change their physical characteristics and biological activities,and thus possess an important potential to be used in the herbicide-resistance breeding.The glycosyltransferase family has numerous members and their functions are diverse.The catalytic substrates and functions of most glycosyltransferase members are still unclear,thus deserving of further study.According to the open access database of gene expression,the Arabidopsis glycosyltransferase gene UGT91C1 is possibly up-regulated by the induction of herbicides.So this gene may be involved in the detoxification of herbicides.In order to clarify specific effect of glycosyltransferase UGT91C1 on herbicides,and then to explore the potential use of plant glycosyltransferase in the process of herbicide-resistance breeding,this research is carried out.The main research contents and results of this study are as follows:The wild-type Arabidopsis thaliana was subjected to the herbicide-treaments and the analysis on the expression level of UGT91C1 by qRT-PCR.The results showed that UGT91C1 was up-regulated by several herbicides.In vitro biochemical analysis of glycosyltransferase activity demonstrated that sulcotrione can be glycosylated by UGT91C1.By comparing the contents of sulcotrione-glycoside in UGT91 Cl transgenic plants and wild-type Arabidopsis thaliana,the in vivo enzymatic activity of UGT91C1 towards sulcotrione was also confirmed.In further experiments,the role of UGT91C1 in the herbicide resistance was analysed by using UGT91C1 overexpressing lines and mutants.We found that the growth of the leaves of UGT91C1 overexpressing lines after sulcotrione treatment was better than the wild-type,while more serious damage was observed in mutant lines.By comparing the chlorophyll contents of UGT91C1 overexpressed lines,mutants and wild-type leaves after sulcotrione treatment,it was found that the chlorophyll content of overexpressed lines was higher than that of wild-type,whereas mutant lines accumulated less chlorophyll content than wild type.After the treatment of detached leaves with sulcotrione.it was found that leaf albinism was easier to occur in mutants and wild type than in overexpression lines.Due to the main effects of sulcotrione on tyrosine metabolic pathway in plants,we investigated the expression levels of those genes on the tyrosine pathway in the UGT91C1 transgenic line and the wild type after sulcotrione treatment.Our qRT-PCR analysis indicated that the upstream genes of target enzyme of sulcotrione were up-regulated in overexpression and down-regulated in mutant,while the downstream genes showed the opposite changes.These results suggest that the UGT91C1 can affect tyrosine metabolism by glycosylating sulcotrione to reduce the toxicity of sulcotrione.In summary,our work demonstrates that Arabidopsis thaliana glycosyltransferase UGT91C1 can glucosylate the herbicide sulcotrione and is involved in the resistance to herbicide.This work further enriches the detoxification role of plant glycosyltransferases on xenobiotics,and provides new ideas for the next functional research of glycosyltransferases.In addition,the UGT91C1 may be used as a novel gene in the herbicide resistance breeding,and provides new directions to cope with the challenges of herbicides in the development of modern agriculture.