Cloning of cDNA and expression analysis of a DnaJ-like gene under heavy metal stress in bean

A clone of PvSR6 encoding a new member of the DnaJ-like protein family was isolated from a mercuric-chloride-treated bean (Phaseolus vulgaris L. ) cDNA library by differential screening using cDNAs derived from treated and untreated plants. The predicted protein contains the highly conserved J domain only, which is present in all DnaJ-like proteins and is considered to play a critical role in DnaJ protein-protein interactions. PvSR6 gene is constitu-tively expressed in roots but weakly expressed in stems and leaf tissue. Northern blot analysis revealed the transcripts of PvSR6 were at low levels in unstressed bean leaves, but the genes expression was strongly stimulated by heavy metals. These suggest that the PvSR6 might play an important role in resistance to the damage caused by heavy metals.