Over-expression of tobacco NtHSP70-1 contributes to drought-stress tolerance in plants

• DOI: 10.1007/s00299-005-0093-2
• Publication Date: 2005-12-19T14:19:24Z
• Authors: Eun Kyung Cho; Choo Bong Hong
• Keywords: Nicotiana; 0303 health sciences; Time Factors; Gene Expression; Water; HSP72 Heat-Shock Proteins; 15. Life on land; Plants, Genetically Modified; 6. Clean water; Disasters; Plant Leaves; 03 medical and health sciences; Desiccation; Plant Proteins

HSP70, a heat shock protein, is a molecular chaperone responsive to various environmental stresses. Here, NtHSP70-1 was a drought-/ABA-inducible gene. We monitored the expression of CaERD15 (early responsive to dehydration) with exposing plants to progressive drought stress. Its activity was used as an indicator of water-deficit conditions. To analyze the protective role of HSP70, we obtained transgenic tobacco plants that constitutively expressed elevated levels of the tobacco HSP70, NtHSP70-1, as well as transgenic plants containing either the vector alone or else having NtHSP70-1 in the antisense orientation. Plants with enhanced levels of NtHSP70-1 in their transgenic sense lines exhibited tolerance to water stress. Under progressive drought, the amount of leaf NtHSP70-1 was correlated with maintenance of optimum water content, with contents being higher in the leaves of dehydrated transgenic sense plants than in those of either the control (vector-only) or the transgenic antisense plants. Moreover, the expression of CaERD15 was considerably reduced in tobacco plants that over-expressed NtHSP70-1. These results suggest that elevated levels of NtHSP70-1 can confer drought-stress tolerance.