Response Of Glucosinolate In Arabidopsis Thaliana To UV-B Radiation

Increasing UV-B radiation reaching the earth’s surface can affect the growth and development of plants. Glucosinolates (GS) are nitrogen-and sulphur-containing secondary metabolites derived from amino acid in Brassicaceae. Glucosinolate metabolism is evolved through plant interactions with the environment and constantly regulated by different environmental factors. Here we report the profiles of glucosinolates and the expression of related genes in response to UV-B radiation (40μW·cm-2) for7days in model plant Arabidopsis thaliana.The result showed that there was no significant difference in relative water contents of rosette leaves in mature and young plant, and chlorophyll a/b ratio in mauture plant between the treatment and the control after UV-B exposure. It suggests that the intensity of UV-B used in our research is not harmful to A. thaliana. Results may also indicate under this UV-B radiation, plants have the ability for self-repair.The expression of several transcription factor genes (MYB28and MYB76) and key genes (CYP79F1, CYP79F2, CYP83A1, CYP79B2and CYP79B3) involved in glucosinolate biosynthesis down-regulated in young plants. In mature plants, UV-B exposure led to the down-regulation of transcription factor genes {MYB34and MYB76) and key genes (CYP79F1, CYP79F2and CYP79B3) involved in glucosinolate core structure biosynthesis. During non-UV-B stage, the contents of GS increased. At the end of the dark cycle, the aliphatic GS8MSOO of both young and mature plants is higher than control, and5MSOP of mature plants is lower, all of the others recovered to the level of control. For indolic glucosinolates,4MOI3M of young plants and DM of mature recovered to the level of control, I3M of young and1MOI3M of mature plants are significantly higher than that of control, but the1MOI3M of young and4MOI3M of mature plants are opposite. The GS total content of mature are higher than that of young plants, but the decreased amplitude of young plants (41.76%) are higher than that of mature (15.32%) after UV-B exposure, which may be related to the different defense mechanisms.The expression of transcription factor genes and key genes involved in glucosinolate biosynthesis down-regulated in both young plants and mature plants of A. thaliana, which may be the reason that the profile of GS has changed. In response to long term and low dose UV-B radiation, the profiles of glucosinolates and the expression of related genes in A. thaliana should change to prevent themselves from the hurt of UV-B radiation.