Transcriptomic and epigenomic remodeling occurs during vascular cambium periodicity in Populus tomentosa

Abstract

Trees in temperate regions exhibit evident seasonal patterns, which play vital roles in their growth and development. The activity of cambial stem cells is the basis for regulating the quantity and quality of wood, which has received considerable attention. However, the underlying mechanisms of these processes have not been fully elucidated. Here we performed a comprehensive analysis of morphological observations, transcriptome profiles, the DNA methylome, and miRNAs of the cambium in Populus tomentosa during the transition from dormancy to activation. Anatomical analysis showed that the active cambial zone exhibited a significant increase in the width and number of cell layers compared with those of the dormant and reactivating cambium. Furthermore, we found that differentially expressed genes associated with vascular development were mainly involved in plant hormone signal transduction, cell division and expansion, and cell wall biosynthesis. In addition, we identified 235 known miRNAs and 125 novel miRNAs. Differentially expressed miRNAs and target genes showed stronger negative correlations than other miRNA/target pairs. Moreover, global methylation and transcription analysis revealed that CG gene body methylation was positively correlated with gene expression, whereas CHG exhibited the opposite trend in the downstream region. Most importantly, we observed that the number of CHH differentially methylated region (DMR) changes was the greatest during cambium periodicity. Intriguingly, the genes with hypomethylated CHH DMRs in the promoter were involved in plant hormone signal transduction, phenylpropanoid biosynthesis, and plant–pathogen interactions during vascular cambium development. These findings improve our systems-level understanding of the epigenomic diversity that exists in the annual growth cycle of trees.

Increased cuticular wax deposition does not change residual foliar transpiration

“…Populus is a genus known for its ease of propagation and breeding, fast growth, usefulness in phytoremediation and reforestation, high wood quality and its utilisation in bio-economy (B. Chen et al, 2021;Dillen et al, 2010;Flathman & Lanza, 1998;Kim & Zsuffa, 1994;Taylor, 2002). Several of its species have been sequenced to date (Lin et al, 2018;T.…”

“…In recent years, poplar trees have been chosen as model species for trees in plant sciences (Bradshaw et al, 2000; Jansson & Douglas, 2007; Tuskan et al, 2006). Populus is a genus known for its ease of propagation and breeding, fast growth, usefulness in phytoremediation and reforestation, high wood quality and its utilisation in bio‐economy (B. Chen et al, 2021; Dillen et al, 2010; Flathman & Lanza, 1998; Kim & Zsuffa, 1994; Taylor, 2002). Several of its species have been sequenced to date (Lin et al, 2018; T. Ma et al, 2013; J. Ma et al, 2019; Mader et al, 2016; Qiu et al, 2019; Tuskan et al, 2006; Zhang et al, 2020).…”

Genome-Wide Characterization and Abiotic Stresses Expression Analysis of Annexin Family Genes in Poplar

“…They have unique profiles and characterizations, such as primary and secondary growth and metabolism and response to environmental stresses. Poplars show some resistance systems, including cell structure changes and signal transduction [ 32 , 33 , 34 ]. They are generally exposed to recurrent damages by various biotic and abiotic stresses.…”

Non-Coding RNA Analyses of Seasonal Cambium Activity in Populus tomentosa

“…Cambium materials were separated from wood blocks which were obtained on 3 January, 20 March, and 22 June 2015. The wood blocks were put into liquid nitrogen immediately and the isolation of vascular cambium from wood blocks was referred to the method described in our previous research [ 33 , 37 ].…”