In temperature stress, the main role of heat-shock proteins (HSP) is to act as molecular chaperones for other cellular proteins. However, knowledge about the hormonal regulation of the production of the HSP is quite limited. Specifically, little is known about the role of the plant steroid hormones—brassinosteroids (BR)—in regulating the HSP expression. The aim of our study was to answer the question of how a BR deficit or disturbances in its signaling affect the accumulation of the HSP90, HSP70, HSP18, and HSP17 transcripts and protein in barley growing at 20 °C (control) and during the acclimation of plants at 5 °C and 27 °C. In barley, the temperature of plant growth modified the expression of HSPs. Furthermore, the BR-deficient mutants (mutations in the HvDWARF
genes) and BR-signaling mutants (mutation in the HvBRI1
gene) were characterized by altered levels of the transcripts and proteins of the HSP group compared to the wild type. The BR-signaling mutant was characterized by a decreased level of the HSP
transcripts and heat-shock proteins. In the BR-deficient mutants, there were temperature-dependent cases when the decreased accumulation of the HSP70
transcripts was connected to an increased accumulation of these HSP. The significance of changes in the accumulation of HSPs during acclimation at 27 °C and 5 °C is discussed in the context of the altered tolerance to more extreme temperatures of the studied mutants (i.e., heat stress and frost, respectively).
This is an open access article distributed under the Creative Commons Attribution License
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited