Abstract: Calnexin,an important lectin-like chaperone in endoplasm reticulum,can assist in protein fol-(ding) and modulate Ca²⁺ homeostasis in cell.A cDNA of 1964 bp encoding a full-length calnexin was cloned from Lycopersicon esculentum,and designated as(Lecnx61.0).A single copy of(Lecnx61.0) was found in tomato genomic DNA by Southern-blot analysis.The levels of mRNA and protein of(Lecnx61.0) were increased when plants were treated by heat shock,chilling shock,salinity stress and endoplasm reticulum stress,but(Lecnx61.0) had no obvious response to drought stress.The protein of(LeCNX61.0) only in speci-(fic) tissues made response to Ca²⁺ depletion.Howerver,the expression of(LeCNX61.0) was not induced by high concentration of Ca²⁺.These results suggested that(LeCNX61.0) might play an important role in stress tolerance.