title: Synechocystis PCC6803 and PCC6906 dnaK2 expression confers salt and oxidative stress tolerance in Arabidopsis via reduction of hydrogen peroxide accumulation.
abstract: Abiotic stress slows plant growth and development. Because salt stress, particularly from NaCl, acts as an important limiting factor in agricultural productivity, the identification and manipulation of genes related to salt tolerance could improve crop productivity. Prokaryotic, heat shock protein (Hsp), DnaK from the ubiquitous Hsp70 family is upregulated in cells that are under abiotic stress. Synechocystis spp. cyanobacteria encode at least three potential DnaK proteins in their genome. Here, expressions of dnaK1s and dnaK2s from two Synechocystis spp. PCC6803 (Sy6803) and PCC6906 (Sy6906), enhanced salt tolerance in a dnaK-defective Escherichia coli strain. In contrast, dnaK3s in both strains were ineffective, indicating that dnaK3 is functionally different from dnaK1 and dnaK2 in Synechocystis spp. under salt stress. Ectopic expression of dnaK2s from Sy6803 and Sy6906 conferred salt tolerance in transgenic Arabidopsis plants, which exhibited greater root length, chlorophyll content, fresh weight, and survival rate than wild type plants, all in the presence of NaCl. In transgenic plants, hydrogen peroxide (H2O2) accumulation was reduced under NaCl stress and loss of chlorophyll content was reduced under H2O2 stress. Overall results suggest that dnaK2s from Sy6803 and Sy6906 confer salt and oxidative tolerance in transgenic plants by reduction of H2O2 accumulation.
authors.affiliation: Greenbio Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Taejon, 305-806, Korea.
authors.forename: Jonghyun
authors.initials: J
authors.lastname: Kim
authors.forename: Myung Suk
authors.initials: MS
authors.lastname: Ahn
authors.forename: Young Min
authors.initials: YM
authors.lastname: Park
authors.forename: Suk Weon
authors.initials: SW
authors.lastname: Kim
authors.forename: Sung Ran
authors.initials: SR
authors.lastname: Min
authors.forename: Weon Joong
authors.initials: WJ
authors.lastname: Jeong
authors.forename: Jang R
authors.initials: JR
authors.lastname: Liu
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D006861:Hydrogen Peroxide / Q000633:toxicity; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development; D055049:Salt Tolerance / Q000235:genetics*; D012965:Sodium Chloride / Q000633:toxicity; D046939:Synechocystis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D018840:HSP70 Heat-Shock Proteins; D012965:Sodium Chloride; D006861:Hydrogen Peroxide