Overexpression of AtHsp90.2, AtHsp90.5 and AtHsp90.7 in Arabidopsis thaliana enhances plant sensitivity to salt and drought stresses.
Three AtHsp90 isoforms, cytosolic AtHsp90.2, chloroplast-located AtHsp90.5, and endoplasmic reticulum (ER)-located AtHsp90.7, were characterized by constitutive overexpressing their genes in Arabidopsis thaliana. Both types of the transgenic plants overexpressing cytosolic and organellar AtHsp90s showed reduced tolerance to salt and drought stresses with lower germination rates and fresh weights, but improved tolerance to high concentration of Ca(2+) comparing with the wild type plants. Transcriptional analysis of ABA-responsive genes, RD29A, RD22 and KIN2 under salt and drought stresses, indicated that the induction expression of these genes was delayed by constitutive overexpression of cytosolic AtHsp90.2, but was hardly affected by that of organellar AtHsp90.5 and AtHsp90.7. These results implied that Arabidopsis different cellular compartments-located Hsp90s in Arabidopsis might be involved in abiotic stresses by different functional mechanisms, probably through ABA-dependent or Ca(2+) pathways, and proper homeostasis of Hsp90 was critical for cellular stress response and/or tolerance in plants.
Song
Hongmiao
H
Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China.
Zhao
Rongmin
R
Fan
Pengxiang
P
Wang
Xuchu
X
Chen
Xianyang
X
Li
Yinxin
Y
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015152:Blotting, Northern; D002122:Calcium Chloride / Q000494:pharmacology; D055864:Droughts; D004591:Electrophoresis, Polyacrylamide Gel; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D008353:Mannitol / Q000494:pharmacology; D030821:Plants, Genetically Modified; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055049:Salt Tolerance / Q000235:genetics / Q000502:physiology*; D012965:Sodium Chloride / Q000494:pharmacology
D029681:Arabidopsis Proteins; D018841:HSP90 Heat-Shock Proteins; C543879:Hsp90-2 protein, Arabidopsis; C543880:Hsp90-5 protein, Arabidopsis; C543881:Hsp90-7 protein, Arabidopsis; D020033:Protein Isoforms; C080922:RD22 protein, Arabidopsis; C520629:RD29a protein, Arabidopsis; C075575:KIN 2 protein, Arabidopsis; D008353:Mannitol; D012965:Sodium Chloride; D002122:Calcium Chloride