Isolation and characterization of a heat-induced gene, hcit2, encoding a novel 16.5 kDa protein: expression coincides with heat-induced tolerance to chilling stress.
Heat treatment of tomato fruits induces tolerance to chilling injury. We have previously shown that specific heat-shock proteins (HSPs) are expressed in heated tomato fruits after cold storage. To search for heat-induced genes that are expressed at low temperatures, a cDNA library prepared from pre-heated chilled tomato fruits was differentially screened. A novel cDNA clone, hcit2, encoding a protein of ca. 16.5 kDa, was isolated. The predicted protein contains three putative trans-membrane hydrophobic sequences, suggesting that the protein is membrane-localized. The expression of hcit2 in fruits was induced by high temperature, but not by other stresses such as low temperature, drought or anaerobic conditions, and not during fruit ripening. A high level of hcit2 transcript was found in heated fruits after 2 weeks at 2 degrees C. High temperatures also induced hcit2 expression in tomato leaves, flowers and stems. The HCIT2 protein may be involved in the acquisition of tolerance to chilling injury.
Adnan
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S
Kennedy-Leigh Centre for Horticultural Research, Hebrew University of Jerusalem, Rehovot, Israel.
Susan
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L
Weiss
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D000595:Amino Acid Sequence; D001483:Base Sequence; D003080:Cold Temperature; D018744:DNA, Plant / Q000737:chemistry / Q000302:isolation & purification*; D018506:Gene Expression Regulation, Plant; D006360:Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics*; D006358:Hot Temperature; D018551:Solanum lycopersicum / Q000235:genetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010940:Plant Proteins
D018744:DNA, Plant; D006360:Heat-Shock Proteins; D010940:Plant Proteins; C111230:hcit2 protein, plant