Over-expression of tobacco NtHSP70-1 contributes to drought-stress tolerance in plants.
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.
Cho
Eun Kyung
EK
Institute of Molecular Biology and Genetics and School of Biological Sciences, Seoul National University, Seoul 151-742, Korea. choeun@snu.ac.kr
Hong
Choo Bong
CB
D003890:Desiccation; D004190:Disasters; D015870:Gene Expression; D050884:HSP72 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D013997:Time Factors; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
D050884:HSP72 Heat-Shock Proteins; D010940:Plant Proteins; D014867:Water