The Heat Shock Response in a Photoautotrophic Cell Culture of Chenopodium rubrum: The Effects of Temperature and Light

Abstract

Summary Heat shock treatment (HS) of the photoautotrophic cell culture of Chenopodium rubrum leads to a rapid synthesis of specific heat shock proteins (HSPs These HSPs belong to the well-known classes of the HSP80-, HSP70- and HSP20-families, and are fairly stable proteins. The steady-state concentration of the specific HS mRNAs, as well as the amount of in vivo labelled HSPs, show similar increments with increasing temperature up to 38 °C at standard light intensities, indicating a regulation primarily at the level of transcription. The effect of light intensities on the induction of HSP was investigated. It was found that with increasing light intensities the temperature at which the maximal HSP induction is achieved declines from 40 °C to 36 °C. Since high light intensities alone cannot induce HS gene expression, but can stimulate the HS response, we propose that light acts as a co-effector on HS transcription and might help to prevent cell damage from the adverse effects of light.