Characterisation of a pine MYB that regulates lignification

Patzlaff, Astrid; McInnis, Stephanie; Courtenay, Adrian; Surman, Christine; Newman, Lisa J.; Smith, Caroline M.; Bevan, Michael W.; Mansfield, Shawn D.; Whetten, Ross; Sederoff, Ronald R.; Campbell, Malcolm M.

doi:10.1046/j.1365-313x.2003.01916.x

Cited by 299 publications

(280 citation statements)

References 72 publications

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“…1 have been identified, and many of the enzymatic steps have been down-regulated in transgenic plants. The results of these studies (24)(25)(26)(27)(28)(29)(30) have generally confirmed the pathway in Fig. 1 and supported increasing S͞G ratio as a means of improving paper pulping in trees.…”

supporting

confidence: 72%

Targeted down-regulation of cytochrome P450 enzymes for forage quality improvement in alfalfa ( Medicago sativa L.)

Reddy

Chen

Shadle

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

316

328

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Improving the digestibility of forages provides a means to enhance animal performance and protect the environment against excessive animal waste. Increased lignin content during maturity, and corresponding changes in lignin composition, correlate with decreased digestibility of forages. These relationships have yet to be investigated in isogenic systems. By targeting three specific cytochrome P450 enzymes of the lignin pathway for antisense downregulation, we generated transgenic alfalfa lines with a range of differences in lignin content and composition. There was a strong negative relationship between lignin content and rumen digestibility, but no relationship between lignin composition and digestibility, in these transgenic lines. Models for genetic manipulation of forage digestibility based on the changes in lignin composition that increase paper-pulping efficiency in trees are therefore invalid. Down-regulation of 4-coumarate 3-hydroxylase provided the largest improvements in digestibility yet seen in a forage crop.forage digestibility ͉ lignin modification ͉ metabolic engineering

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supporting

confidence: 72%

Targeted down-regulation of cytochrome P450 enzymes for forage quality improvement in alfalfa ( Medicago sativa L.)

Reddy

Chen

Shadle

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

316

328

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“…Several genes encoding enzymes in the general phenylpropanoid pathway and in the synthesis of lignin precursors contain common motifs that are recognized by specific transcription factors, such as MYBs (Borevitz et al, 2000;Patzlaff et al, 2003). The QTLs we identified here could represent such transcription factors.…”

Section: Discussionmentioning

confidence: 82%

“…Indole-3-acetic acid has been shown to function as a positional signal for xylem differentiation (Uggla et al, 1998;Mellerowicz et al, 2001). Specific transcription factors, such as members of the R2R3-MYB gene family, are also likely to control lignification during xylogenesis (Patzlaff et al, 2003). Despite the progress in defining the molecular and cellular processes involved, the mechanisms that determine the rate of xylogenesis (wood growth) and variation in wood properties remain largely unknown.…”

mentioning

confidence: 99%

Coordinated Genetic Regulation of Growth and Lignin Revealed by Quantitative Trait Locus Analysis of cDNA Microarray Data in an Interspecific Backcross of Eucalyptus

Kirst

Myburg²,

León³

et al. 2004

Plant Physiology

193

169

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Phenotypic, genotypic, and transcript level (microarray) data from an interspecific backcross population of Eucalyptus grandis and Eucalyptus globulus were integrated to dissect the genetic and metabolic network underlying growth variation. Transcript abundance, measured for 2,608 genes in the differentiating xylem of a 91 (E. grandis 3 E. globulus) 3 E. grandis backcross progeny was correlated with diameter variation, revealing coordinated down-regulation of genes encoding enzymes of the lignin biosynthesis and associated methylation pathways in fast growing individuals. Lignin analysis of wood samples confirmed the content and quality predicted by the transcript levels measured on the microarrays. Quantitative trait locus (QTL) analysis of transcript levels of lignin-related genes showed that their mRNA abundance is regulated by two genetic loci, demonstrating coordinated genetic control over lignin biosynthesis. These two loci colocalize with QTLs for growth, suggesting that the same genomic regions are regulating growth, and lignin content and composition in the progeny. Genetic mapping of the lignin genes revealed that most of the key biosynthetic genes do not colocalize with growth and transcript level QTLs, with the exception of the locus encoding the enzyme S-adenosylmethionine synthase. This study illustrates the power of integrating quantitative analysis of gene expression data and genetic map information to discover genetic and metabolic networks regulating complex biological traits.Wood is composed of secondary xylem, a highly specialized conductive and structural support tissue produced by lateral growth and differentiation of the meristematic vascular cambium (Fukuda, 1996). Genes expressed during the developmentally regulated process of xylogenesis determine the physical and chemical properties of wood. The product of xylogenesis represents one of the world's most important natural resources, yet relatively little is known about the genetic regulation of this process. Wood serves as a renewable source of energy, and it is a sink for atmospheric carbon. Wood is also the raw material for the global pulp and paper, and timber industries. The growth and development of trees and other woody plants are fundamental determinants of the dynamics and composition of forest ecosystems.At the plant cell level, growth is determined by cell division and expansion. Expansion is driven primarily by internal osmotic pressure generated by water uptake. Expansion is constrained by the cell wall and depends on cell wall composition and the degree of association between its different components (Buchanan et al., 2000). Growth of secondary xylem results from a sequential developmental process that begins with cambial cell division, followed by cell expansion, secondary wall formation, lignification, and programmed cell death (Fukuda, 1996). Wood growth has been associated with the number and rate of cell divisions at the meristematic cambium (Gregory and Wilson, 1968;Wilson and Howard, 1968;Zobel and van Buijtenen, 1989...

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“…Similar results were also reported for loblolly pine MYB1 and MYB4 (Patzlaff et al ., 2003a,b). PgNAC‐7 and these three MYBs were proposed by Duval et al .…”

Section: Discussionmentioning

confidence: 99%

“…The other genes that were connected to PgMYB8 , PgMYB4 and PgNAC‐7 , suggesting that their regulation depends on several transcription factors. These results support observations that several different MYBs may act in concert to regulate different portions of phenylpropanoid metabolism and lignin biosynthesis at different times in conifer trees (Patzlaff et al ., 2003a; Bomal et al ., 2014). …”

Section: Discussionmentioning

confidence: 99%

Genetic architecture of wood properties based on association analysis and co‐expression networks in white spruce

et al. 2015

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Summary Association studies are widely utilized to analyze complex traits but their ability to disclose genetic architectures is often limited by statistical constraints, and functional insights are usually minimal in nonmodel organisms like forest trees.We developed an approach to integrate association mapping results with co‐expression networks. We tested single nucleotide polymorphisms (SNPs) in 2652 candidate genes for statistical associations with wood density, stiffness, microfibril angle and ring width in a population of 1694 white spruce trees (Picea glauca).Associations mapping identified 229–292 genes per wood trait using a statistical significance level of P < 0.05 to maximize discovery. Over‐representation of genes associated for nearly all traits was found in a xylem preferential co‐expression group developed in independent experiments. A xylem co‐expression network was reconstructed with 180 wood associated genes and several known MYB and NAC regulators were identified as network hubs. The network revealed a link between the gene PgNAC8, wood stiffness and microfibril angle, as well as considerable within‐season variation for both genetic control of wood traits and gene expression. Trait associations were distributed throughout the network suggesting complex interactions and pleiotropic effects.Our findings indicate that integration of association mapping and co‐expression networks enhances our understanding of complex wood traits.

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Characterisation of a pine MYB that regulates lignification

Cited by 299 publications

References 72 publications

Targeted down-regulation of cytochrome P450 enzymes for forage quality improvement in alfalfa ( Medicago sativa L.)

Targeted down-regulation of cytochrome P450 enzymes for forage quality improvement in alfalfa ( Medicago sativa L.)

Coordinated Genetic Regulation of Growth and Lignin Revealed by Quantitative Trait Locus Analysis of cDNA Microarray Data in an Interspecific Backcross of Eucalyptus

Genetic architecture of wood properties based on association analysis and co‐expression networks in white spruce

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