Article

Important new players in secondary wall synthesis. Trends Plant Sci

Department of Plant Biology, University of Georgia, Athens, GA 30602, USA.
Trends in Plant Science (Impact Factor: 12.93). 05/2006; 11(4):162-4. DOI: 10.1016/j.tplants.2006.02.001
Source: PubMed

ABSTRACT

Secondary walls in wood are the most abundant biomass produced by plants. Understanding how plants make wood is not only of interest in basic plant biology but also has important implications for tree biotechnology. Three recent papers report exciting findings regarding a group of novel glycosyltransferases (GTs) involved in secondary wall synthesis. Because little is known about genes involved in the synthesis of wood polysaccharides other than cellulose, the identification of these GTs is a breakthrough in the molecular dissection of wood formation.

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    • "Secondary walls constitute the bulk of most biofuel feedstocks and thus become a main target for genetic modification (Chundawat et al., 2011; Yang et al., 2013). Secondary wall synthetic genes that have been investigated in this way include, for example, several genes that are involved in cellulose [such as various CesA genes (Joshi et al., 2004Joshi et al., , 2011 Taylor et al., 2004; Brown et al., 2005; Ye et al., 2006 )] and xylan biosynthesis [IRX8 (Brown et al., 2005; Ye et al., 2006; Peña et al., 2007; Oikawa et al., 2010; Liang et al., 2013), IRX9 (Brown et al., 2005; Lee et al., 2007 Lee et al., , 2011a Peña et al., 2007; Oikawa et al., 2010; Liang et al., 2013), IRX9L (Oikawa et al., 2010; Wu et al., 2010), IRX14 (Oikawa et al., 2010; Wu et al., 2010; Lee et al., 2011a), IRX14L (Wu et al., 2010; Lee et al., 2011a), IRX15 (Brown et al., 2011), and IRX15L (Brown et al., 2011)] in dicots. In addition, a number of transcription factors including plant-specific NAC-domain Plant biomass characterization Frontiers in Bioengineering and Biotechnology | www.frontiersin.org "
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    ABSTRACT: Plant biomass is the major renewable feedstock resource for sustainable generation of alternative transportation fuels to replace fossil carbon-derived fuels. Lignocellulosic cell walls are the principal component of plant biomass. Hence, a detailed understanding of plant cell wall structure and biosynthesis is an important aspect of bioenergy research. Cell walls are dynamic in their composition and structure, varying considerably among different organs, cells, and developmental stages of plants. Hence, tools are needed that are highly efficient and broadly applicable at various levels of plant biomass-based bioenergy research. The use of plant cell wall glycan-directed probes has seen increasing use over the past decade as an excellent approach for the detailed characterization of cell walls. Large collections of such probes directed against most major cell wall glycans are currently available worldwide. The largest and most diverse set of such probes consists of cell wall glycan-directed monoclonal antibodies (McAbs). These McAbs can be used as immunological probes to comprehensively monitor the overall presence, extractability, and distribution patterns among cell types of most major cell wall glycan epitopes using two mutually complementary immunological approaches, glycome profiling (an in vitro platform) and immunolocalization (an in situ platform). Significant progress has been made recently in the overall understanding of plant biomass structure, composition, and modifications with the application of these immunological approaches. This review focuses on such advances made in plant biomass analyses across diverse areas of bioenergy research.
    Full-text · Article · Oct 2015 · Frontiers in Bioengineering and Biotechnology
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    • "Wood development has been characterized by expression profiling in aspen [9-11], Pinus [12,13], black locust [14], Eucalyptus [15,16] and spruce [17]. These studies, and investigations on vascular cell development in herbaceous species Arabidopsis and Zinnia, have identified several classes of important transcription regulators and structural genes involved in secondary cell wall biogenesis (reviewed in [8,18,7,19]). The developmental transition from primary to secondary growth that occurs along the stem has been used as a unique system to identify processes specific to secondary growth in sitka spruce [18] and aspen [20,21]. "
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    ABSTRACT: With its genome sequence and other experimental attributes, Populus trichocarpa has become the model species for genomic studies of wood development. Wood is derived from secondary growth of tree stems, and begins with the development of a ring of vascular cambium in the young developing stem. The terminal region of the developing shoot provides a steep developmental gradient from primary to secondary growth that facilitates identification of genes that play specialized functions during each of these phases of growth. Using a genomic microarray representing the majority of the transcriptome, we profiled gene expression in stem segments that spanned primary to secondary growth. We found 3,016 genes that were differentially expressed during stem development (Q-value </= 0.05; >2-fold expression variation), and 15% of these genes encode proteins with no significant identities to known genes. We identified all gene family members putatively involved in secondary growth for carbohydrate active enzymes, tubulins, actins, actin depolymerizing factors, fasciclin-like AGPs, and vascular development-associated transcription factors. Almost 70% of expressed transcription factors were upregulated during the transition to secondary growth. The primary shoot elongation region of the stem contained specific carbohydrate active enzyme and expansin family members that are likely to function in primary cell wall synthesis and modification. Genes involved in plant defense and protective functions were also dominant in the primary growth region. Our results describe the global patterns of gene expression that occur during the transition from primary to secondary stem growth. We were able to identify three major patterns of gene expression and over-represented gene ontology categories during stem development. The new regulatory factors and cell wall biogenesis genes that we identified provide candidate genes for further functional characterization, as well as new tools for molecular breeding and biotechnology aimed at improvement of tree growth rate, crown form, and wood quality.
    Full-text · Article · Mar 2010 · BMC Genomics
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    • "malting and brewing industries (Kuntz and Bamforth, 2007). Although there have been exciting new discoveries in the synthesis of cellulose, pectic polysaccharides, mannans, and xyloglucans in recent years, these discoveries have been made predominantly in dicotyledonous plants (Ye et al., 2006; Mohnen, 2008; Zabotina et al., 2008) and will not be covered here. This update, therefore, will be restricted to recent advances in our understanding of the biosynthesis of the characteristic and major wall polysaccharides of the grasses, namely the heteroxylans and (1,3;1,4)-b-D-glucans. "
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    ABSTRACT: A major part of the daily caloric intake of human societies around the world is derived from a diverse range of foods prepared from members of the grass family, including wheat (Triticum aestivum), rice (Oryza sativa), sorghum (Sorghum bicolor), the millets (Panicum miliaceum and Pennisetum americanum), barley (Hor- deum vulgare), and sugar cane (Saccharum officinarum). Grasses cover perhaps 20% or more of the earth's land surface (Gaut, 2002), and many of these are used as forage and fodder for the production of sheep, cattle, and other domesticated livestock. Maize (Zea mays )i s also used widely in animal feed diets, while sorghum, switchgrass (Panicum virgatum), and several other perennial grasses are attracting considerable attention as future biomass energy crops (McLaren, 2005). The grasses are noteworthy for the unusual compo- sition of their cell walls, because walls of grasses have less pectin and xyloglucan, but more heteroxylan, than walls from other higher plants. Most significantly, walls of the grasses contain as major constituents the (1,3;1,4)-b-D-glucans, which are not widely distributed outside the Poaceae. The compositions of walls from selected barley organs are shown in Table I. In many cases, constituents of cell walls in the grasses are closely linked with their widespread adoption, utility, and future potential in agricultural practice and en- ergy production. The noncellulosic polysaccharides of walls in grasses are important components of dietary fiber, which is highly beneficial for lowering the risk of serious human health conditions, including colorectal cancer, high serum cholesterol and cardiovascular disease, obesity, and non-insulin-dependent diabetes (Braaten et al., 1994; Brennan and Cleary, 2005). Con- versely, the noncellulosic wall polysaccharides from walls of cereals and grasses have antinutritive effects in monogastric animals such as pigs and poultry (Brennan and Cleary, 2005) and are often considered to be undesirable components of raw materials in the
    Preview · Article · Feb 2009 · Plant physiology
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