Flexible and digestible wood caused by viral-induced alteration of cell wall composition

Holly Allen, Leo Zeef, Kris Morreel, Geert Goeminne, Manoj Kumar, Leonardo D Gomez, Andrew P Dean, Axel Eckmann, Cinzia Casiraghi, Simon J McQueen-Mason, Wout Boerjan, Simon R Turner

Research output: Contribution to journalArticlepeer-review


Woody plant material represents a vast renewable resource that has the potential to produce biofuels and other bio-based products with favorable net CO 2 emissions. 1 , 2 Its potential has been demonstrated in a recent study that generated novel structural materials from flexible moldable wood. 3 Apple rubbery wood (ARW) disease is the result of a viral infection that causes woody stems to exhibit increased flexibility. 4 Although ARW disease is associated with the presence of an RNA virus 5 known as apple rubbery wood virus (ARWV), how the unique symptoms develop is unknown. We demonstrate that the symptoms of ARWV infections arise from reduced lignification within the secondary cell wall of xylem fibers and result in increased wood digestibility. In contrast, the mid-lamellae region and xylem ray cells are largely unaffected by the infection. Gene expression and proteomic data from symptomatic xylem clearly show the downregulation of phenylalanine ammonia lyase (PAL), the enzyme catalyzing the first committed step in the phenylpropanoid pathway leading to lignin biosynthesis. A large increase in soluble phenolics in symptomatic xylem, including the lignin precursor phenylalanine, is also consistent with PAL downregulation. ARWV infection results in the accumulation of many host-derived virus-activated small interfering RNAs (vasiRNAs). PAL-derived vasiRNAs are among the most abundant vasiRNAs in symptomatic xylem and are likely the cause of reduced PAL activity. Apparently, the mechanism used by the virus to alter lignin exhibits similarities to the RNAi strategy used to alter lignin in genetically modified trees to generate comparable improvements in wood properties. 6-8.

Original languageEnglish
Pages (from-to)1-16
Number of pages16
JournalCurrent Biology
Early online date17 Jun 2022
Publication statusE-pub ahead of print - 17 Jun 2022

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Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.

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