Phytochelatin is not a primary factor in determining copper tolerance |
| |
Authors: | Sangman Lee Beom Sik Kang |
| |
Institution: | (1) Department of Agricultural Chemistry, Division of Applied Biology and Chemistry, Kyungpook National University, 702-701 Daegu, Korea;(2) School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, 702-701 Daegu, Korea |
| |
Abstract: | Phytochelatin (PC) is involved in the detoxification of harmful, non-essential heavy metals and the homeostasis of essential
heavy metals in plants. Its synthesis can be induced by either cadmium (Cd) or copper (Cu), and can form stable complexes
with either element. This might suggest that PC has an important role in determining plant tolerance to both. However, this
is not clearly apparent, as evidenced by a PC-deficient and Cd-sensitiveArabidopsis mutant (cad1-3) that shows no significant increase in its sensitivity to copper. Therefore, we investigated whether the mechanism for Cu
tolerance differed from that for Cd by analyzing copper sensitivity in Cd-tolerant transgenics and Cd-sensitive mutants ofArabidopsis. Cadmium-tolerant transgenic plants that over-expressedA. thaliana phytochelatin synthase 1 (AtPCS1) were not tolerant of copper stress, thereby supporting the hypothesis that PC is not primarily involved in this tolerance
mechanism. We also investigated Cu tolerance incad2-1, a Cd-sensitive and glutathione (GSH)-deficientArabidopsis mutant. Paradoxically,cad2-1 was more resistant to copper stress than were wild-type plants. This was likely due to the high level of cysteine present
in that mutant. However, when the growth medium was supplemented with cysteine, the wild types also exhibited copper tolerance.
Moreover,Saccharomyces cerevisiae that expressedAtPCS1 showed tolerance to Cd but hypersensitivity to Cu. All these results indicate that PC is not a major factor in determining
copper tolerance in plants. |
| |
Keywords: | Arabidopsis cad1 cad2 cadmium copper phytochelatin |
本文献已被 SpringerLink 等数据库收录! |
|