According to data released by Guangzhou’s Food and Drug Administration, 44 percent of the rice tested in the city of roughly 12 million people showed high cadmium content，which is the newest food scandal triggering anger from consumers in China. Cadmium is a major environmental contaminant that enters human food via accumulation in crop plants, and is considered as being one of the most ecotoxic metals that exhibits adverse effects on all biological processes in humans, animals and plants. The heavy metal can remain in the body for up to 30 years.

Recently, many studies have revealed that overexpression of small heat shock protein （sHSP） genes confered enhanced tolerance against oxidative, UV-B, heat, osmotic, drought and salt stresses in plants. However, the functions of sHSP involved in heavy metal stress are largely unknown. Although previous studies indicated that OsMSR3 was induced by cold, drought, heat and heavy metal stresses, this is the first report that transgenic lines expressing OsMSR3, a sHSP-CI family gene, displayed enhanced Cadmium tolerance.

Using modern molecular biology techniques, a team of researchers from the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) spent 3 years to estimate whether gene OsMSR3 can enhance plant tolerance to cadmium stress.

The researchers found that transgenic Arabidopsis expressing OsMSR3 showed enhanced tolerance to Cd, displaying longer roots, higher survival rates and accumulated more Cd, phytochelatins (PCs), nonprotein thiol (NPT) and glutathione (GSH) than wild type plants under Cd condition. Expression of OsMSR3 conferred enhanced tolerance to Cd in Arabidopsis accompanied by improving expressions of bHLH transcription factors and Cd stress-related genes. Taken together, our results suggested that expression of OsMSR3 in Arabidopsis enhanced tolerance to Cd stress, and OsMSR3 may act as a positive regulator of Cd stress tolerance in plants.

This research was supported by Nitrogen and Phosphorus cycling and manipulation for agro-ecosystems and the Knowledge Innovation program of the Chinese Academy of Sciences (KZCX2-YW-T07) and National Natural Science Foundation of China (31171536).

The study entitled “Expression of OsMSR3 in Arabidopsis enhances tolerance to cadmium stress” has been published in Volume 113, Issue 2, May 2013 of Plant Cell, Tissue and Organ Culture, details could be found at http://link.springer.com/article/10.1007/s11240-012-0275-x