Plastocyanin Gene from Seepweed Improves Oxidative Stress Tolerance in Arabidopsis

Previous studies have indicated that plant plastocyanins are involved in copper homeostasis. However, their physiological relevance remains elusive. The team of Xin-Tong Zhou of Chinese Academy of Sciences found that a plastocyanin gene, SsPETE2, from seepweed (Suaeda salsa) has a novel antioxidant function, which was associated with its copper-chelating activity.

In S. salsa, the expression of SsPETE2 increased when the plant was exposed to oxidative stress. When SsPETE2 was expressed in Arabidopsis, it enhanced the antioxidant ability of the transgenic plants. The SsPETE2 protein binds to Cu ions and alleviate formation of hydroxyl radicals. Thus, SsPETE2 expression lowers the free Cu content that was associated with plants under oxidative stress.

Interestingly, SsPETE2-expressing plants exhibited more potent tolerance to oxidative stress than plants overexpressing AtPETEs. This means that the SsPETE2 protein has a stronger copper-binding activity than AtPETEs protein.

These results demonstrate that plant PETEs play a role in oxidative stress tolerance by regulating Cu ions in plants under stress conditions. SsPETE2, an efficient copper-chelating PETE, could be potentially used in crop genetic engineering.

For more information, read the article in Plant Science.