Light Quality Modulates Plant Cold Response and Freezing Tolerance

Abstract

The cold acclimation process is regulated by many factors like ambient temperature, day length, light intensity, or hormonal status. Experiments with plants grown under different light quality conditions indicate that the plant response to cold is also a light-quality-dependent process. Here, the role of light quality in the cold response was studied in 1-month-old Arabidopsis thaliana (Col-0) plants exposed for 1 week to 4°C at short-day conditions under white (100 and 20 μmol m−2s−1), blue, or red (20 μmol m−2s−1) light conditions. An upregulated expression of CBF1, inhibition of photosynthesis, and an increase in membrane damage showed that blue light enhanced the effect of low temperature. Interestingly, cold-treated plants under blue and red light showed only limited freezing tolerance compared to white light cold-treated plants. Next, the specificity of the light quality signal in cold response was evaluated in Arabidopsis accessions originating from different and contrasting latitudes. In all but one Arabidopsis accession, blue light increased the effect of cold on photosynthetic parameters and electrolyte leakage. This effect was not found for Ws-0, which lacks functional CRY2 protein, indicating its role in the cold response. Proteomics data confirmed significant differences between red and blue light-treated plants at low temperatures and showed that the cold response is highly accession-specific. In general, blue light increased mainly the cold-stress-related proteins and red light-induced higher expression of chloroplast-related proteins, which correlated with higher photosynthetic parameters in red light cold-treated plants. Altogether, our data suggest that light modulates two distinct mechanisms during the cold treatment - red light-driven cell function maintaining program and blue light-activated specific cold response. The importance of mutual complementarity of these mechanisms was demonstrated by significantly higher freezing tolerance of cold-treated plants under white light.

The Effect of White Light Spectrum Modifications by Excess of Blue Light on the Frost Tolerance, Lipid- and Hormone Composition of Barley in the Early Pre-Hardening Phase

“…Later, enhanced levels of cis-zeatin and its riboside were not observed under B supplementation to WFR. This is in accordance with a recent analysis of the expression of CK-related genes like CRF and type-B ARR transcription factors, which are predominantly down-regulated under blue light [ 46 , 61 ]. However, the positive effect of WFRB on frost tolerance seems to be reflected by faster cold acclimation associated with elevated content of the highly physiologically active tZ and its reversible metabolite tZOG (in comparison with W and WFR).…”

“…In Arabidopsis thaliana , it is becoming more and more certain that monochromatic B has a positive effect on frost tolerance [ 47 , 55 ]. B was reported to positively affect cold-stress related proteins, i.e., those associated with defense in Arabidopsis thaliana [ 46 ]. In accordance with this finding, the cold-induced increase in ABA content in barley leaves was further increased by B, as the ABA level was considerably higher after WFRB than in the case of mere WFR supplementation.…”

“…In addition to that, the useful irradiance available at the surface is affected by many atmospheric factors such as aerosol and by the quantity and types of clouds [ 43 , 44 ]. The breakthrough happened in 2021, when several papers describing the possible role of B in Arabidopsis cold acclimation were published [ 45 , 46 , 47 ]. Under cold stress, the B-phosphorylated blue light receptor CRY2 is stabilized and in this state inhibits the degradation of HY5 .…”

“…I Intact HY5 positively regulates freezing tolerance by modulating the expression of a set of COR genes, including some active in anthocyanin biosynthesis [ 48 ]. This process is mainly independent of the CBF pathway [ 46 , 47 ]. To date, all we know about the role of B in the cold hardening process of cereals is that B up-regulates the COR14b protein (one of the targets of CBF s) in barley under cold conditions [ 49 ] and CBF14 in wheat and barley even at higher temperatures, which are not suitable for inducing cold acclimation (20 and 15 °C) [ 6 ].…”

Abiotic Stress in Crop Production

“…An important factor in stress resistance is light. Light is, of course, the primary source of energy for plants but stress responses are also significantly modulated by light conditions [ 464 ]. However, laboratory experiments typically use well-controlled and homogeneous light conditions that differ significantly from the natural variations in the field.…”