Ethylene Signaling Is Required for Fully Functional Tension Wood in Hybrid Aspen

Frontiers in Plant Science

Jonathan W. Love¹  Thomas Vain²  András Gorzsás³  Kamil Antos⁴  Markus Rüggeberg⁶  Björn Sundberg⁷  Nicolas Delhomme⁸  Judith Felten⁸  Hannele Tuominen⁹  Bernard A. Wessels⁹  Carolin Seyfferth⁹ 

[1] Arevo AB, Umeå, Sweden;DIADE, Univ Montpellier, IRD, Montpellier, France;Department of Chemistry, Umeå University, Umeå, Sweden;Department of Integrative Medical Biology, Umeå University, Umeå, Sweden;Institute for Building Materials, Swiss Federal Institute of Technology Zurich (ETH Zurich), Zurich, Switzerland;Laboratory of Wood Materials, Swiss Federal Laboratories of Materials Science and Technology, Dubendorf, Switzerland;Stora Enso AB, Nacka, Sweden;Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden;Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden;

关键词: xylem;    wood;    ethylene;    tension wood;    lignin;    microfibril angle;   

DOI  :  10.3389/fpls.2019.01101

来源: DOAJ

【 摘 要 】

Tension wood (TW) in hybrid aspen trees forms on the upper side of displaced stems to generate a strain that leads to uplifting of the stem. TW is characterized by increased cambial growth, reduced vessel frequency and diameter, and the presence of gelatinous, cellulose-rich (G-)fibers with its microfibrils oriented parallel to the fiber cell axis. Knowledge remains limited about the molecular regulators required for the development of this special xylem tissue with its characteristic morphological, anatomical, and chemical features. In this study, we use transgenic, ethylene-insensitive (ETI) hybrid aspen trees together with time-lapse imaging to show that functional ethylene signaling is required for full uplifting of inclined stems. X-ray diffraction and Raman microspectroscopy of TW in ETI trees indicate that, although G-fibers form, the cellulose microfibril angle in the G-fiber S-layer is decreased, and the chemical composition of S- and G-layers is altered than in wild-type TW. The characteristic asymmetric growth and reduction of vessel density is suppressed during TW formation in ETI trees. A genome-wide transcriptome profiling reveals ethylene-dependent genes in TW, related to cell division, cell wall composition, vessel differentiation, microtubule orientation, and hormone crosstalk. Our results demonstrate that ethylene regulates transcriptional responses related to the amount of G-fiber formation and their properties (chemistry and cellulose microfibril angle) during TW formation. The quantitative and qualitative changes in G-fibers are likely to contribute to uplifting of stems that are displaced from their original position.

【 授权许可】

Unknown