Transgenic phytochrome D cooperates with phytochrome B to promote photomorphogenesis at low temperatures.
6 affiliations
- 1Laboratory of Photo and Chronobiology, Institute of Plant Biology, Biological Research Centre, Hungarian Research Network (HUN-REN), Szeged, 6726, Hungary.
- 2Faculty of Sciences and Informatics, Doctoral School of Biology, University of Szeged, Szeged, 6726, Hungary.
- 3Metabolic Systems Biology Laboratory, HCEMM-BRC, and Genomic Epidemiology Research Group, HUN-REN-BRC-ELTE-SZTE-NNGyK, Szeged, 6726, Hungary.
- 4Synthetic and Systems Biology Unit, Biological Research Centre, Institute of Biochemistry, Hungarian Research Network (HUN-REN), Szeged, 6726, Hungary.
- 5Laboratory of Photo and Chronobiology, Institute of Plant Biology, Biological Research Centre, Hungarian Research Network (HUN-REN), Szeged, 6726, Hungary. [email protected].
- 6Laboratory of Photo and Chronobiology, Institute of Plant Biology, Biological Research Centre, Hungarian Research Network (HUN-REN), Szeged, 6726, Hungary. [email protected].
Abstract
Key message
The function of the phytochrome B photoreceptor is enhanced by its homologous counterpart, phytochrome D, at low temperatures, thereby increasing phenotypic plasticity in response to fluctuating environmental conditions. Light is a dynamically changing environmental factor that influences nearly every aspect of plant growth and development. Photoreceptors detect light, with phytochromes (PHY) specifically monitoring red and far-red wavelengths. Arabidopsis thaliana has five phytochromes, named phyA through phyE. phyA and phyB are extensively studied key mediators of most phytochrome responses; the precise functions of the other phytochromes remain poorly understood. To investigate phyD signaling, we overexpressed phyD-YFP alone and together with phyB-CFP in a genetic background lacking other phytochromes. Photomorphogenic responses, protein accumulation, and transcriptome changes were compared at low and high temperatures. We found that phyD-YFP alone cannot facilitate photomorphogenesis, but it significantly promotes red light signaling of both phyB-CFP and endogenous phyB in a temperature-dependent manner, being effective at low but not at high temperatures. In parallel, co-expressing phyD-YFP and phyB-CFP triggered substantially more robust light-induced transcriptome changes at low temperatures than expressing either transgene alone. Because phyD-YFP is more light-stable than phyB, and both PHYB-CFP and endogenous PHYB accumulate to higher levels alongside PHYD-YFP in light, phyD likely stimulates phyB signaling via PHYB protein stabilization. To explain how PHYD-YFP enhances PHYB levels at both temperatures yet stimulates signaling exclusively at low temperatures, we propose that phyD and phyB form light-stable heterodimers at both temperatures and that these heterodimers are functional only at low temperatures. Our findings demonstrate that phyB and phyD functionally cooperate to mediate temperature-dependent light signaling responses, providing plants with developmental flexibility under changing environmental conditions.
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BibTeX
@article{sipos2026transgenic,
title = {{Transgenic phytochrome D cooperates with phytochrome B to promote photomorphogenesis at low temperatures.}},
author = {Lilla Sípos and Gábor Grézal and Csaba Péter and Ferenc Nagy and Dániel Silhavy and András Viczián},
journal = {Plant cell reports},
year = {2026},
month = oct,
doi = {10.1007/s00299-026-04025-y},
url = {https://europepmc.org/article/MED/42909509},
note = {CC BY},
}
RIS
TY - JOUR
TI - Transgenic phytochrome D cooperates with phytochrome B to promote photomorphogenesis at low temperatures.
AU - Lilla Sípos
AU - Gábor Grézal
AU - Csaba Péter
AU - Ferenc Nagy
AU - Dániel Silhavy
AU - András Viczián
PY - 2026
DA - 2026/10/23
JO - Plant cell reports
DO - 10.1007/s00299-026-04025-y
UR - https://europepmc.org/article/MED/42909509
AB - Key message The function of the phytochrome B photoreceptor is enhanced by its homologous counterpart, phytochrome D, at low temperatures, thereby increasing phenotypic plasticity in response to fluctuating environmental conditions. Light is a dynamically changing environmental factor that influences nearly every aspect of plant growth and development. Photoreceptors detect light, with phytochromes (PHY) specifically monitoring red and far-red wavelengths. Arabidopsis thaliana has five phytochromes, named phyA through phyE. phyA and phyB are extensively studied key mediators of most phytochrome responses; the precise functions of the other phytochromes remain poorly understood. To investigate phyD signaling, we overexpressed phyD-YFP alone and together with phyB-CFP in a genetic background lacking other phytochromes. Photomorphogenic responses, protein accumulation, and transcriptome changes were compared at low and high temperatures. We found that phyD-YFP alone cannot facilitate photomorphogenesis, but it significantly promotes red light signaling of both phyB-CFP and endogenous phyB in a temperature-dependent manner, being effective at low but not at high temperatures. In parallel, co-expressing phyD-YFP and phyB-CFP triggered substantially more robust light-induced transcriptome changes at low temperatures than expressing either transgene alone. Because phyD-YFP is more light-stable than phyB, and both PHYB-CFP and endogenous PHYB accumulate to higher levels alongside PHYD-YFP in light, phyD likely stimulates phyB signaling via PHYB protein stabilization. To explain how PHYD-YFP enhances PHYB levels at both temperatures yet stimulates signaling exclusively at low temperatures, we propose that phyD and phyB form light-stable heterodimers at both temperatures and that these heterodimers are functional only at low temperatures. Our findings demonstrate that phyB and phyD functionally cooperate to mediate temperature-dependent light signaling responses, providing plants with developmental flexibility under changing environmental conditions.
SN - 0721-7714
SN - 1432-203X
ER -