Low-temperature and circadian signals are integrated by the sigma factor SIG5.

Authors :: Cano-Ramirez DL
Panter PE
Takemura T
de Fraine TS
de Barros Dantas LL
Dekeya R
Barros-Galvão T
Paajanen P
Bellandi A
Batstone T
Manley BF
Tanaka K
Imamura S
Franklin KA
Knight H
Dodd AN
Source :: Nature plants [Nat Plants] 2023 Apr; Vol. 9 (4), pp. 661-672. Date of Electronic Publication: 2023 Mar 30.
Publication Year :: 2023
Abstract: Chloroplasts are a common feature of plant cells and aspects of their metabolism, including photosynthesis, are influenced by low-temperature conditions. Chloroplasts contain a small circular genome that encodes essential components of the photosynthetic apparatus and chloroplast transcription/translation machinery. Here, we show that in Arabidopsis, a nuclear-encoded sigma factor that controls chloroplast transcription (SIGMA FACTOR5) contributes to adaptation to low-temperature conditions. This process involves the regulation of SIGMA FACTOR5 expression in response to cold by the bZIP transcription factors ELONGATED HYPOCOTYL5 and ELONGATED HYPOCOTYL5 HOMOLOG. The response of this pathway to cold is gated by the circadian clock, and it enhances photosynthetic efficiency during long-term cold and freezing exposure. We identify a process that integrates low-temperature and circadian signals, and modulates the response of chloroplasts to low-temperature conditions.<br /> (© 2023. The Author(s).)