Bark tissue transcriptome analyses of inverted Populus yunnanensis cuttings reveal the crucial role of plant hormones in response to inversion

An-Pei Zhou; Pei-Hua Gan; Dan Zong; Xuan Fei; Yuan-Yuan Zhong; Si-Qi Li; Jin-De Yu; Cheng-Zhong He

doi:10.7717/peerj.7740

Bark tissue transcriptome analyses of inverted Populus yunnanensis cuttings reveal the crucial role of plant hormones in response to inversion

PeerJ. 2019 Oct 1:7:e7740. doi: 10.7717/peerj.7740. eCollection 2019.

Authors

An-Pei Zhou^{1

2}, Pei-Hua Gan^{1

2}, Dan Zong^{1

2}, Xuan Fei^{1

2}, Yuan-Yuan Zhong^{1

2}, Si-Qi Li^{1

2}, Jin-De Yu¹, Cheng-Zhong He^{1

2

3}

Affiliations

¹ Key Laboratory for Forest Genetic and Tree Improvement and Propagation in Universities of Yunnan Province, Southwest Forestry University, Kunming, China.
² Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming, China.
³ Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, China.

Abstract

Inverted cuttings of Populus yunnanensis exhibit an interesting growth response to inversion. This response is characterized by enlargement of the stem above the shoot site, while the upright stem shows obvious outward growth below the shoot site. In this study, we examined transcriptome changes in bark tissue at four positions on upright and inverted cuttings of P. yunnanensis: position B, the upper portion of the stem; position C, the lower portion of the stem; position D, the bottom of new growth; and position E, the top of new growth. The results revealed major transcriptomic changes in the stem, especially at position B, but little alteration was observed in the bark tissue of the new shoot. The differentially expressed genes (DEGs) were mainly assigned to four pathways: plant hormone signal transduction, plant-pathogen interaction, mitogen-activated protein kinase (MAPK) signaling pathway-plant, and adenosine triphosphate-binding cassette (ABC) transporters. Most of these DEGs were involved in at least two pathways. The levels of many hormones, such as auxin (IAA), cytokinin (CTK), gibberellins (GAs), ethylene (ET), and brassinosteroids (BRs), underwent large changes in the inverted cuttings. A coexpression network showed that the top 20 hub unigenes at position B in the upright and inverted cutting groups were associated mainly with the BR and ET signaling pathways, respectively. Furthermore, brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1) in the BR pathway and both ethylene response (ETR) and constitutive triple response 1 (CTR1) in the ET pathway were important hubs that interfaced with multiple pathways.

Keywords: Bark tissues; Hub gene; Inversion; Populus yunnanensis; Transcriptome.

Associated data

figshare/10.6084/m9.figshare.7973858.v2

Grants and funding

This work was supported by the National Natural Science Foundation of China (Nos. 31860219 and 31360184). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.