A nuclear-localized HSP70 confers thermoprotective activity and drought-stress tolerance on plants.
To investigate the function of nuclear-localized plant HSP70, we used NtHSP70-1 isolated from Nicotiana tabacum. The subcellular localization of NtHSP70-1 was identified by fluorescence microscopy for NtHSP70-1/GFP or smGFP fusion proteins in onion epidermal cells, obtained using particle gun bombardment. To analyze the drought-stress tolerance and thermoprotective role of NtHSP70-1, we obtained transgenic tobacco plants that constitutively expressed elevated levels of NtHSP70-1 as well as transgenic plants containing either the vector alone or else having NtHSP70-1 in the antisense orientation. From analysis for genomic DNA in transgenic seedlings after heat stress, NtHSP70-1 helps to prevent the fragmentation and degradation of nuclear DNA during heat stress. In addition, seedlings constitutively overexpressing NtHSP70-1 grew to be healthy plants, whereas transgenic vector or antisense seedlings resulted in death after heat-/drought-stress.
Cho
Eun Kyung
EK
Department of Bio-Food Materials, College of Medical Life Science, Silla University, Busan 617-736, South Korea. choeun@silla.ac.kr
Choi
Young Ju
YJ
D002467:Cell Nucleus / Q000737:chemistry*; D002478:Cells, Cultured; D053938:DNA Fragmentation; D018744:DNA, Plant / Q000378:metabolism; D055864:Droughts; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis*; D006358:Hot Temperature; D019697:Onions / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000235:genetics; D013312:Stress, Physiological; D014026:Nicotiana / Q000235:genetics / Q000502:physiology*
D018744:DNA, Plant; D018840:HSP70 Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins