Mechanical load induces upregulation of transcripts for a set of genes implicated in secondary wall formation in the supporting tissue of Arabidopsis thaliana

Koizumi, Kento; Yokoyama, Ryusuke; Nishitani, Kazuhiko

doi:10.1007/s10265-009-0251-7

Cited by 15 publications

(19 citation statements)

References 51 publications

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“…LAC4 expression was observed in both vascular bundles and interfascicular fibers, whereas LAC17 expression seemed to be more specific to fibers. These results are consistent with the expression profile determined in another study using the same reporter gene (Koizumi et al, 2009).…”

Section: Laccase Gene Expression Profiles In Arabidopsis Stems and Thsupporting

confidence: 92%

Disruption of LACCASE4 and 17 Results in Tissue-Specific Alterations to Lignification of Arabidopsis thaliana Stems

et al. 2011

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Peroxidases have been shown to be involved in the polymerization of lignin precursors, but it remains unclear whether laccases (EC 1.10.3.2) participate in constitutive lignification. We addressed this issue by studying laccase T-DNA insertion mutants in Arabidopsis thaliana. We identified two genes, LAC4 and LAC17, which are strongly expressed in stems. LAC17 was mainly expressed in the interfascicular fibers, whereas LAC4 was expressed in vascular bundles and interfascicular fibers. We produced two double mutants by crossing the LAC17 (lac17) mutant with two LAC4 mutants (lac4-1 and lac4-2). The single and double mutants grew normally in greenhouse conditions. The single mutants had moderately low lignin levels, whereas the stems of lac4-1 lac17 and lac4-2 lac17 mutants had lignin contents that were 20 and 40% lower than those of the control, respectively. These lower lignin levels resulted in higher saccharification yields. Thioacidolysis revealed that disrupting LAC17 principally affected the deposition of G lignin units in the interfascicular fibers and that complementation of lac17 with LAC17 restored a normal lignin profile. This study provides evidence that both LAC4 and LAC17 contribute to the constitutive lignification of Arabidopsis stems and that LAC17 is involved in the deposition of G lignin units in fibers.

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Section: Laccase Gene Expression Profiles In Arabidopsis Stems and Thsupporting

confidence: 92%

Disruption of LACCASE4 and 17 Results in Tissue-Specific Alterations to Lignification of Arabidopsis thaliana Stems

et al. 2011

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“…Arabidopsis PME35, which was classified as a member of the type I/group 2 PME subfamily, was shown to be expressed preferentially in the basal part of the inflorescence stem (Yokoyama and Nishitani, 2006) (see Supplemental Figure 1 online). We also found that this gene was upregulated significantly in response to the application of 50 mg of weight to the stem and, conversely, downregulated when the stem was placed in a horizontal position (Yokoyama and Nishitani, 2006;Koizumi et al, 2009). These findings suggest that PME35 is involved in pectin-mediated strengthening of supporting tissue in the basal part of the Arabidopsis stem.…”

Section: Introductionmentioning

confidence: 59%

Demethylesterification of the Primary Wall by PECTIN METHYLESTERASE35 Provides Mechanical Support to the Arabidopsis Stem

et al. 2012

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Secondary cell walls, which contain lignin, have traditionally been considered essential for the mechanical strength of the shoot of land plants, whereas pectin, which is a characteristic component of the primary wall, is not considered to be involved in the mechanical support of the plant. Contradicting this conventional knowledge, loss-of-function mutant alleles of Arabidopsis thaliana PECTIN METHYLESTERASE35 (PME35), which encodes a pectin methylesterase, showed a pendant stem phenotype and an increased deformation rate of the stem, indicating that the mechanical strength of the stem was impaired by the mutation. PME35 was expressed specifically in the basal part of the inflorescence stem. Biochemical characterization showed that the activity of pectin methylesterase was significantly reduced in the basal part of the mutant stem. Immunofluorescence microscopy and immunogold electron microscopy analyses using JIM5, JIM7, and LM20 monoclonal antibodies revealed that demethylesterification of methylesterified homogalacturonans in the primary cell wall of the cortex and interfascicular fibers was suppressed in the mutant, but lignified cell walls in the interfascicular and xylary fibers were not affected. These phenotypic analyses indicate that PME35-mediated demethylesterification of the primary cell wall directly regulates the mechanical strength of the supporting tissue.

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“…This result suggested that the signal transduction pathways that linked mechanical sensing to transcriptional regulation of secondary wallrelated genes were mediated via AtMYB103 and SND3. In contrast, the expression of the NST1 gene was found to be only slightly affected under the same conditions (Koizumi et al, 2009). Given that NST1 and NST3/ SND1 function as master switches for secondary growth by controlling the other transcription factors including SND3 and AtMYB103, its less sensitive response to the weight load implies that the mechanical signals may be transmitted via a novel transduction pathway that is mediated by the actions of AtMYB103 and SND3, but are independent of NST1 and NST3/SND1.…”

Section: Approach Based On Application Of Loadmentioning

confidence: 88%

“…In contrast, Koizumi et al applied a 50-mg weight to the stem of A. thaliana plants grown under continuous light conditions, and examined the effects of load application on transcript levels of 15 Type C profile cell wall-related genes that had been identified in secondary wall formation in the supporting tissues of the basal part of the stem via quantitative real time RT-PCR analysis (Koizumi et al, 2009). Using this approach, Koizumi et al found that 12 of the 15 genes examined were significantly up-regulated following load application (Table II).…”

Section: Approach Based On Application Of Loadmentioning

confidence: 99%

“…These genes included those encoding β-1,4-glucanase (CEL2, KOR), cellulose synthase (CesA4, CesA7), chitinase (CTL2), β-galactosidase (BGAL4), laccase (LAC2, IRX4, LAC17), peroxidase (PER42), pectin esterase (PME61) and endopolygalacturonase (PG43), some of which have been characterized previously (Blee et al, 2003;Brown et al, 2005;Cai et al, 2006;Szyjanowicz et al, 2004;Taylor et al, 2003;Taylor et al, 1999;Zhong et al, 2002) . Koizumi et al also examined the effects of load application on the transcription factors implicated in secondary wall formation in the interfascicular and xylem fibers, and revealed that AtMYB103 and SND3 were significantly up-regulated in response to load application (Koizumi et al, 2009). This result suggested that the signal transduction pathways that linked mechanical sensing to transcriptional regulation of secondary wallrelated genes were mediated via AtMYB103 and SND3.…”

Section: Approach Based On Application Of Loadmentioning

confidence: 99%

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Cell Wall-Related Genes Involved in Supporting Tissue Formation and Transcriptional Regulation in Arabidopsis thaliana

2009

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The characteristic growth pattern of vascular p l a n t s l a r g e l y d e p e n d s o n t h e i n t r i n s i c p ro p e r t i e s of t h e ir c e ll wa lls , whic h a r e flexible, but strong enough to support the plant body. The plant body is composed of various tissues each with a specific cell wall type. Different sets of enzymes are required for the construction of these individual cell wall types. The cell wall type-specific enzyme-set hypothesis has been described to explain the mechanisms underlying cell wall construction. This hypothesis suggests that specific sets of transcription factors are required for the construction of each of the cell-wall types. Recent reverse genetic studies investigating secondary wall formation in Arabidopsis thaliana have demonstrated the existence of a hierarchical transcriptional network that governs the regulation of secondary wall formation in cell wall types. The examination of the effects of mechanical stimuli on the expression of genes encoding a particular set of cell wall-related enzymes and transcriptional factors has shown that A. thaliana is able to perceive subtle changes in self-weight of the aerial portions, and use this information as a signal to regulate formation of cell walls in the supporting tissues. However, the mechanisms by which mechanical signals are perceived via sensors presumably located at the cell surface remain unknown. In addition, the pathways through which the signal is transmitted and integrated into the transcriptional network that governs the coordinated actions of cell wallrelated genes are also yet to be described. Current reverse genetic approaches based on comprehensive expression analysis of cell wall-related genes may aid in the elucidation of the regulatory mechanisms underlying supporting tissue formation via mechanical signals. Such information may contribute not only to a further understanding of the molecular basis underlying evolution of the plant vascular system, but may also provide us with the knowledge required for the future development and utilization of plant cell walls as a sustainable resource.

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Mechanical load induces upregulation of transcripts for a set of genes implicated in secondary wall formation in the supporting tissue of Arabidopsis thaliana

Cited by 15 publications

References 51 publications

Disruption of LACCASE4 and 17 Results in Tissue-Specific Alterations to Lignification of Arabidopsis thaliana Stems

Disruption of LACCASE4 and 17 Results in Tissue-Specific Alterations to Lignification of Arabidopsis thaliana Stems

Demethylesterification of the Primary Wall by PECTIN METHYLESTERASE35 Provides Mechanical Support to the Arabidopsis Stem

Cell Wall-Related Genes Involved in Supporting Tissue Formation and Transcriptional Regulation in Arabidopsis thaliana

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