cDNA-AFLP analysis of inducible gene expression in zinc hyperaccumulator Sedum alfredii Hance under zinc induction

Sedum alfredii Hance (S. alfredii) has been identified as a zinc hyperaccumulating plant species from heavy metal polluted areas of China. In this study, a cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis was employed to identify differentially expressed genes of hyperaccumulating S. alfredii compared with non-hyperaccumulating S. alfredii, under Zn treatment in hydroponic culture. Both the hyperaccumulator and non-hyperaccumulator were treated for 0 h, 24 h and 8 d with 500 μM Zn(NO3)2 and 50 μM Zn(NO3)2, respectively. Twenty-two transcript-derived fragments (TDFs) were identified as Zn responsive fragments in hyperaccumulating S. alfredii compared with the non-hyperaccumulator. Sixteen TDFs had significant matches in the NCBI database and six TDFs had no significant matches. In addition, the full-length cDNA sequences of the actin gene were cloned from the two ecotypes of S. alfredii by RT-PCR and RACE, and used as an internal standard for the confirmation of gene expression in hyperaccumulating S. alfredii by real-time PCR.