Arabidopsis SUMO E3 ligase SIZ1 is involved in excess copper tolerance
Many heavy metals are essential as trace nutrients for living organisms. These essential heavy metals can also cause toxicity at high levels. Plants have evolved a range of homeostasis mechanisms to minimize the harmful effects and maintain the concentration of essential metals within physiological limits. Arabidopsis mutant defective on the SUMO E3 ligase, atsiz1, is very sensitive to excess Cu. We found that excess Cu induced SIZ1 dependent SUMOylation. In addition, this process is involved in the gene regulation of transporters YSL1 and YSL3. By examining the gene expression patterns and through functional studies of mutants, the involvement of YSL1 and YSL3 regulation in the control of Cu translocation is proposed. This report suggests that SIZ1-mediated sumoylation is involved in copper homeostasis and tolerance in planta.
