High-throughput screening of Oryza sativa genes enhancing yeast Cd tolerance

Abstract

A cDNA library prepared from Oryza sativa var Nipponbare seedlings was used to transform a cadmium (Cd)-sensitive budding yeast strain, Δycf1, to identify genes enhancing Cd tolerance. Of the 3 x 10⁵ cDNA clones initially screened, 5 Cd-tolerant clones were obtained, including two encoding metallothioneins and one encoding OsCDT1, a cysteine-rich 55-amino acid peptide homolog of Digitaria ciliaris CDT1. Another clone, termed OsCdR1, conferred Cu²⁺ tolerance in addition to Cd²⁺ tolerance to the yeast cells, but showed no differences in terms of Ni²⁺, Co²⁺, Mn²⁺ or Zn²⁺ tolerance compared to control yeast cells. To evaluate the role of OsCdR1 in planta, transgenic Arabidopsis and rice plants are currently being generated.