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Review
. 2018 Dec 17;9:1873.
doi: 10.3389/fpls.2018.01873. eCollection 2018.

Environmentally Sensitive Molecular Switches Drive Poplar Phenology

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Free PMC article
Review

Environmentally Sensitive Molecular Switches Drive Poplar Phenology

Jay P Maurya et al. Front Plant Sci. .
Free PMC article

Abstract

Boreal and temperate woody perennials are highly adapted to their local climate, which delimits the length of the growing period. Moreover, seasonal control of growth-dormancy cycles impacts tree productivity and geographical distribution. Therefore, traits related to phenology are of great interest to tree breeders and particularly relevant in the context of global warming. The recent application of transcriptional profiling and genetic association studies to poplar species has provided a robust molecular framework for investigating molecules with potential links to phenology. The environment dictates phenology by modulating the expression of endogenous molecular switches, the identities of which are currently under investigation. This review outlines the current knowledge of these molecular switches in poplar and covers several perspectives concerning the environmental control of growth-dormancy cycles. In the process, we highlight certain genetic pathways which are affected by short days, low temperatures and cold-induced signaling.

Keywords: adaptive response; bud set; circadian clock; cold response; low ambient temperature; poplar; short day; winter dormancy.

Figures

FIGURE 1
FIGURE 1
Bud set-associated genes in poplar are sensitive to low ambient temperature. (A) Bud set scores for hybrid poplar (Populus tremula x P. alba) plants grown under SD and three different temperatures (21, 18, and 15°C) for 9 weeks. (B) Comparative analysis of hybrid poplar bud stage progression in plants grown under SD and three different temperatures (21, 18, and 15°C) over 4 weeks. Asterisks denote significant differences between hybrid poplar plant groups (n = 8) grown at different temperatures (Kruskal–Wallis test followed by pairwise Wilcox test; P < 0.05, ∗∗P < 0.01). (C) Venn diagram representing the intersection between genes with SNPs associated with bud set and that show robust diurnal oscillations (cut-off = 0.8) under light/dark cycles (LD) and constant temperature (25°C, HH) or photothermocycles (25°C during the day, 12°C during the night, HC). 172 genes (lilac) show robust diurnal rhythms only under LDHH, 134 genes (pink) show diurnal rhythms only under LDHC and 135 genes (fuchsia) oscillate under both conditions, respectively. (D,E) Clusters of genes that show diurnal expression within 0–11 h under LDHC (D, mean = pink) and within 12–23 h under LDHC (E, mean = pink). The line chart demonstrates how photothermocycles (LDHC) promote diurnal oscillation of poplar PDLDELTA (D) and CBF4 genes (E). (F,G) Clusters of genes that show diurnal expression within 0–11 h under LDHH (F, mean = lilac) and within 12–23 h under LDHH (G, mean = lilac). The line chart demonstrates how photothermocycles (LDHC) disrupt the diurnal oscillation of poplar CCR1 (F) and PUR7 genes (G).
FIGURE 2
FIGURE 2
Photoperiodic and temperature control of bud set, dormancy establishment and bud break. Short days promote bud set via activation of Flowering locus D1 (FLD1) and Abscisic acid insensitive 3 (ABI3) (Tylewicz et al., 2015), the ethylene and ABA pathways (Rohde et al., 2002; Ruonala et al., 2006) as well as the circadian clock pathway (Hoffman et al., 2010; Ibañez et al., 2010). The timing of bud set is sensitive to low ambient temperature, which alters the expression of the circadian pathway (Figure 1). ABA plays an essential role in dormancy establishment by promoting plasmodesmata closure via PKL repression (Tylewicz et al., 2018) and activating SVL growth repressive gene (Singh et al., 2018). Increased exposure to chilling temperatures is necessary to the downregulation of ABA and degradation of growth repressors such as CENL1 (Karlberg et al., 2010; Mohamed et al., 2010; Tylewicz et al., 2018). Dormancy release increases gibberellin levels (Rinne et al., 2011), mediates plasmodesmata opening (Tylewicz et al., 2018) and activates bud break-promoting factors such as FT1 (Hsu et al., 2011; Rinne et al., 2011), EBB1 (Yordanov et al., 2014), and DML10 (Conde et al., 2017). Long days and warm temperatures restore shoot apical growth.

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References

    1. Amasino R. (2004). Vernalization, competence, and the epigenetic memory of winter. Plant Cell 16 2553–2559. 10.1105/tpc.104.161070 - DOI - PMC - PubMed
    1. Bastow R., Mylne J. S., Lister C., Lippman Z., Martienssen R. A., Dean C. (2004). Vernalization requires epigenetic silencing of FLC by histone methylation. Nature 427 164–167. 10.1038/nature02269 - DOI - PubMed
    1. Benedict C., Skinner J. S., Meng R., Chang Y., Bhalerao R., Huner N. P. A., et al. (2006). The CBF1-dependent low temperature signalling pathway, regulon and increase in freeze tolerance are conserved in Populus spp. Plant Cell Environ. 29 1259–1272. 10.1111/j.1365-3040.2006.01505.x - DOI - PubMed
    1. Bieniawska Z., Espinoza C., Schlereth A., Sulpice R., Hincha D. K., Hannah M. A. (2008). Disruption of the Arabidopsis circadian clock is responsible for extensive variation in the cold-responsive transcriptome. Plant Physiol. 147 263–279. 10.1104/pp.108.118059 - DOI - PMC - PubMed
    1. Böhlenius H., Huang T., Charbonnel-Campaa L., Brunner A. M., Jansson S., Strauss S. H., et al. (2006). CO/FT regulatory module controls timing of flowering and seasonal growth cessation in trees. Science 312 1040–1043. 10.1126/science.1126038 - DOI - PubMed

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