A role of Hsp90 chaperones in stabilization of plant growth and morphogenesis in gamma-irradiated Arabidopsis thaliana seeds
Abstract
An insight into the molecular basis of survival and renewal of the irradiated seeds is important for the reliable functioning of plant systems during long space and planetary missions. We have investigated a role of HSP90 chaperones in protection of Arabidopsis thaliana seeds against radiation damage. HSP90 are important in the maturation and conformational regulation of a diverse set of proteins that regulate key steps in different biological processes. It has been supposed that HSP90s can prevent a part of cryptic genetic changes from displaying in a phenotype [Queitsch et al., 2002]. So reduction of HSP90 functioning may destabilize development and uncover some cryptic genetic variations that can increase phenotypic variability. Moreover, binding of Hsf, HSP90s may negatively regulate HSP expression - an important component of the stress reaction. To study this, dry A. thaliana (Ler) seeds were exposed to gamma-radiation (100-1000 Gy) and treated with geldanamycin (GDA) - an inhibitor of HSP90. The affect of cosmic radiation was simulated by gamma rays irradiation from the radioactive isotope cobalt-60 (15 rads at 23ºC). A significant increase in variability in growth rates and phenotypes as well as appearance of strong morphological abnormalities were detected in the seedlings grown from the irradiated seeds. GDA treatment resulted in 1.5-2-fold increase in a number of altered phenotypes. In addition, the antibiotic essentially stimulated the seedling growth after irradiation, but this effect was time-lagged at 500-1000 Gy. It was also shown that GDA treatment induced HSP synthesis. These results indicate diverse cellular functions of HSP90: autoregulation of stress reaction, restoration after geno- and cytotoxic effects, concealment of genetic changes and stabilization of plant development.
- Publication:
-
40th COSPAR Scientific Assembly
- Pub Date:
- 2014
- Bibcode:
- 2014cosp...40E1623K