The Effect Of UV-B Radiation On Glucosinolate Metabolism In Arabidopsis

Glucosinolates (GS) are nitrogen-and sulphur-containing secondary metabolites in Cruciferae. We determined GS content and related gene expression in response to enhanced UV-B radiation (0.145 mW/cm2) and the succeeding dark recovery process in model plant Arabidopsis thaliana.The result showed that there was no significant difference in relative water contents and membrane permeability of rosette leaves between the treatment and the control after 1 h of UV-B exposure. After 3 h of UV-B exposure, relative water contents decreased and membrane permeability increased. Along with further UV-B exposure (12 h), the damage to membrane turned obviously worse. After 12 h of the succeeding dark recovery, the damage caused by enhanced UV-B radiation could be partially recovered.At the initial 3 h of enhanced UV-B radiation, UV-B signaling might trigger the increase of two main GS (4MSOB and I3M) contents in rosette leaves by activating the expression of several transcription factor genes (OBP2, MYB51, IQD1, MYB28 and MYB76) and key genes involved in glucosinolate core structure biosynthesis (MAM3, SOT16 and SOT17).12 h of UV-B exposure led to the downregulation of majority of GS metabolism related genes and GS total contents in leaves. After 12 h of the succeeding dark recovery, GS total contents recovered to the levels as the control. Simultaneously GS metabolism related genes (MYB34, CYP79B3, SUR1, SOT16, CYP81F2, MYB28, MAM3, CYP79F2, CYP83A1 and SOT17) expressed to or over the levels of the control.In the initial 3 h of UV-B exposure and the succeeding dark recovery process, several representative genes (JAZ1, MYC2, COI1, AOC4, ATERF1 and ASC4) involved in JA and ET signaling systems upregulated, which maybe regulate the biosynthesis of GS or other secondary metabolites after UV-B radiation. So this phenomenon might relieve the damage effect of UV-B radiation on plants.