When grown under cool temperature, winter annuals upregulate
photosynthetic capacity as well as freezing tolerance. Here, the role of
three cold-induced C-repeat-Binding Factor (CBF1–3) transcription
factors in photosynthetic upregulation and freezing tolerance was
examined in two Arabidopsis thaliana ecotypes originating from Italy
(IT) or Sweden (SW), and their corresponding CBF1–3-deficient mutant
lines it:cbf123 and sw:cbf123. Photosynthetic, morphological, and
freezing-tolerance phenotypes as well as gene expression profiles were
characterized in plants grown from seedling stage under different
combinations of light level and temperature. Under high light and cool
growth temperature (HLC), a greater role of CBF1–3 in IT versus SW was
evident from both phenotypic and transcriptomic data, especially with
respect to photosynthetic upregulation and freezing tolerance of whole
plants. Overall, features of SW were consistent with a different
approach to HLC acclimation than seen in IT, and an ability of SW to
reach the new homeostasis through involvement of transcriptional
controls other than CBF1–3. These results provide tools and direction
for further mechanistic analysis of the transcriptional control of
approaches to cold acclimation suitable for either persistence through
brief cold spells or for maximization of productivity in environments
with continuous low temperatures.
Deep evolutionary origin of gamete-directed zygote activation by KNOX/BELL transcription factors in green plants
