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Crop Biotech Update

SaHMA3 Functions in Cadmium Hyperaccumulation and Tolerance of Sedum alfredii

February 24, 2016

Understanding the mechanism of how hyperaccumulator plants accumulate and tolerate extremely toxic metals is vital for developing strategies for phytoremediation using engineered plants or natural hyperaccumulators.

Sedum alfredii Hance, a metal hyperaccumulator from the Crassulaceae family, is an ideal candidate for gaining understanding of the hyperaccumulation mechanisms as well as its potential applications. Zhejiang University's Jie Zhang led researchers to characterize a P1B-type ATPase gene (SaHMA3) from S. alfredii Hance.

SaHMA3 alleles from a hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) were analyzed. The SaHMA3h allele from the HE plant was found to be a Cadmium transporter while SaHMA3n from NHE plants was a transporter of both Zinc and Cadmium.

The SaHMA3 gene was found to be expressed significantly higher in HE plants than in NHE plants. Furthermore, the expression level of SaHMA3 in the shoots of HE plants was considerably higher than in the roots. Overexpression of SaHMA3h in tobacco plants significantly enhanced its Cadmium tolerance and accumulation.

These results suggest that SaHMA3 plays critical roles in Cd hyperaccumulation and hypertolerance in S. alfredii Hance.

For more information, read the article on Planta.