title: Identification and characterization of a heat-inducible Hsp70 gene from Sorghum bicolor which confers tolerance to thermal stress.
abstract: This study describes the first detailed molecular characterization of the heat shock protein 70 (Hsp70) gene from Sorghum bicolor, MN1618 designated as SbHsp70-1. The full-length cDNA of SbHsp70-1 consists of 2524 bp with a 1950 bp open reading frame, which encodes a protein of 649 amino acids. SbHsp70-1 is a cytoplasmic protein with high homology to other plant Hsp70s, especially grain crops. Recombinant SbHsp70-1 was able to bind and hydrolyse ATP in a dose-dependent manner, suggesting that SbHsp70-1 functions as an ATPase. Immunoblot assays showed that the expression of SbHsp70-1 is induced at temperatures of 37, 45, and 4 °C but reduced at 42 °C. In addition, the SbHsp70-1 mRNA transcript is constitutively expressed in both leaves and stem but is significantly increased upon heat shock at 42 °C. Upon cold shock at 4 °C, SbHsp70-1 mRNA transcript level increased in the leaf, but no significant change was observed in the stem. In addition, expression of the pET28a-SbHsp70-1 construct in Escherichia coli cells under heat stress resulted in their survival even at higher temperature (65 °C). Our results suggest that SbHsp70-1 is a heat-inducible protein that confer thermal tolerance to bacterial cells and can be claimed as a promising target to study stress tolerance in crops.
authors.affiliation: Proteomics Research and Services Unit, Department of Biotechnology, University of the Western Cape, Level 2-New Life Sciences Building, Modderdam Road, Private Bag X17, Bellville, 7535, Cape Town, South Africa.
authors.forename: Takalani
authors.initials: T
authors.lastname: Mulaudzi-Masuku
authors.forename: Rendani Daphney
authors.initials: RD
authors.lastname: Mutepe
authors.forename: Ofhani Christopher
authors.initials: OC
authors.lastname: Mukhoro
authors.forename: Andrew
authors.initials: A
authors.lastname: Faro
authors.forename: Bongani
authors.initials: B
authors.lastname: Ndimba
mesh_terms: D018076:DNA, Complementary; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000235:genetics*; D018869:Heat-Shock Response; D006358:Hot Temperature; D012689:Sequence Homology, Nucleic Acid; D045868:Sorghum / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D018840:HSP70 Heat-Shock Proteins