Treatment Analogous to Seasonal Change Demonstrates the Integration of Cold Responses in Brachypodium distachyon

Abstract

Anthropogenic climate change precipitates the need to understand plant adaptation. Crucial in temperate climates, adaptation to winter is characterized by cold acclimation and vernalization, which respectively lead to freezing tolerance and flowering competence. However, the progression of these responses during fall and their interaction with plant development are not completely understood. By identifying key seasonal cues found in the native range of the cereal model Brachypodium distachyon, we designed a diurnal-freezing treatment (DF) that emulates summer-to-winter change. DF induced unique cold acclimation and vernalization responses characterized by low VERNALIZATION1 (VRN1) expression. Flowering under DF is characterized by an up-regulation of FLOWERING LOCUS T (FT) postvernalization independent of VRN1 expression. DF, while conferring flowering competence, favors a high tolerance to freezing and the development of a winter-hardy plant structure. The findings of this study highlight the contribution of phenotypic plasticity to freezing tolerance and demonstrate the integration of key morphological, physiological, and molecular responses in cold adaptation. The results suggest a fundamental role for VRN1 in regulating cold acclimation, vernalization, and morphological development in B. distachyon. This study also establishes the usefulness of reproducing natural cues in laboratory settings.

Transcriptional memories mediate the plasticity of cold stress responses to enable morphological acclimation in Brachypodium distachyon

“…Chromatin immunoprecipitation was performed for three biological replicates as previously described (Mayer et al ., 2015), using antibodies anti‐Histone H3 (cat. no.…”

TheBrachypodium distachyoncold-acclimated plasma membrane proteome is primed for stress resistance

“…A striking 483-fold elevation in relative abundance at CA2 was observed for COR410-like (Bradi3g51200.1), a dehydrin family cold-regulated protein. Transcripts encoding this protein have previously been shown to accumulate after low-temperature exposure in Brachypodium (Mayer et al 2020) and orthologous COR47 (At1g20440.1), as well as the related COR78 (At5g52310.1), also showed relative increases in abundance after CA of Arabidopsis (Miki et al 2019). It is thought that dehydrins, which are intrinsically disordered PM-associated proteins, act as chaperones to prevent protein denaturation during dehydration (Singh et al 2019).…”

“…This result suggests at least a partially conserved response to low-temperature between Brachypodium and Arabidopsis at the PM. It is not surprising that they are not identical considering their evolutionary distance and the differences in freezing tolerance as determined by their capacity to survive low-temperatures after CA, with Arabidopsis at -6 to -11 °C, depending on the accession, vs. Brachypodium at -12°C ; (Kaplan et al 2004;Hannah et al 2006;Mayer et al 2020).…”

“…Evidence shows that Brachypodium evolved in Mediterranean regions and some cultivars tolerate low-temperatures (Ryu et al 2014;Colton-Gagnon et al 2014;Bredow et al 2016). Following CA, these survive to -10 °C (Colton-Gagnon et al 2014) with a diurnal freezing treatment allowing tolerance down to -12 °C (Mayer et al 2020). Here, we examine the profile of compatible solutes accumulated after CA, quantify cold-induced membrane protection, and present the first proteomic analysis of cold-acclimated (CA) Brachypodium from PM-enriched microsomal fractions in order to further advance our understanding of freeze-tolerance and the low-temperature protection in this model monocot.…”

The Relationships between Plant Developmental Traits and Winter Field Survival in Rye (Secale cereale L.)

“…In the freezing tests, the LT 50 values were determined on plants cold acclimated under constant exposure to 4 • C temperature, low light intensity, and a short-day cycle. These growth room conditions do not include the frequent variations in light intensity and temperature that naturally occur in the field, which constitute environmental signals that can prime plants to increase their cold acclimation [58]. Such triggering events may include a short cold spell prior to a longer period of cold or exposure to slightly subzero temperatures, initiating a second hardening step [30,59].…”