| Summary: | Calnexin (CNX) is an integral membrane protein that functions as a chaperone in the endoplasmic reticulum for the correct folding of proteins under stress conditions, rendering organisms tolerant under adverse conditions. Studies have investigated the cytogenetic effects of gamma irradiation (Ɣ-IR) on plants, but information on the molecular response under Ɣ-IR remains limited. Previously, we constructed a cDNA library of an irradiation-sensitive bioindicator plant, <i>Tradescantia</i> BNL4430 (T-4430) under Ɣ-IR, in which the <i>Calnexin-1</i> gene was highly upregulated at 50 mGy treatment. <i>TrCNX1</i> encodes a 61.4 kDa protein with conserved signature motifs similar to already reported <i>CNX1</i>s. <i>TrCNX1</i> expression was evaluated by semiquantitative reverse transcriptase PCR and quantitative real-time PCR and was ubiquitously expressed in various tissues and highly upregulated in flower petals under 50 mGy Ɣ-IR stress. The protective function of <i>TrCNX1</i> was investigated by overexpression of TrCNX1 in an <i>Escherichia coli</i> BL21(DE3) heterologous system. Using plate assay, we showed that TrCNX1 increased the viability of <i>E</i>. <i>coli</i> transformants under both UV-B and Ɣ-IR compared with the control, demonstrating that <i>TrCNX1</i> functions under irradiation stress. <i>TrCNX1</i> may enhance irradiation stress tolerance in crops and act as a radio marker gene to monitor the effects of radiation.
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