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Philip J. Harris - One of the best experts on this subject based on the ideXlab platform.
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Occurrence of fucosylated and non-fucosylated xyloglucans in the cell walls of Monocotyledons: An immunofluorescence study
Plant physiology and biochemistry : PPB, 2019Co-Authors: Maree Brennan, Diyana Fakharuzi, Philip J. HarrisAbstract:The xyloglucans of Monocotyledons are known to vary in the abundance of fucosylated side chains, with most commelinid Monocotyledons having xyloglucans with lower proportions than non-commelinid Monocotyledons. In many commelinid species, and some non-commelinid species that have lower proportions of fucosylated side chains, these side chains have been shown to be cell-type specific. To determine whether it is just the fucosylated side chains that are cell-type specific, or whether xyloglucan is cell-type specific in these species, we used the monoclonal antibody LM15 in conjunction with immmunofluorescence microscopy. We examined the distribution of cell-wall labelling among cell types in these species. The primary walls of all cell types were shown to contain xyloglucans in all species that had cell-type specific distributions of fucosylated side chains. This indicates that it is the fucosylated side chains of xyloglucans that is cell-type specific. Although the functional significance of xyloglucan fucosylation remains unknown, such cell-type specificity supports hypotheses that the fucosylated side chains may indeed have a functional role within the cell wall.
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Commelinid Monocotyledon Lignins Are Acylated by p-Coumarate.
Plant physiology, 2018Co-Authors: Steven D. Karlen, Bronwen G Smith, Heather C.a. Free, Dharshana Padmakshan, John Ralph, Philip J. HarrisAbstract:Commelinid Monocotyledons are a monophyletic clade differentiated from other Monocotyledons by the presence of cell wall-bound ferulate and p-coumarate. The Poaceae, or grass family, is a member of this group, and most of the p-coumarate in the cell walls of this family acylates lignin. Here, we isolated and examined lignified cell wall preparations from 10 species of commelinid Monocotyledons from nine families other than Poaceae, including species from all four commelinid Monocotyledon orders (Poales, Zingiberales, Commelinales, and Arecales). We showed that, as in the Poaceae, lignin-linked p-coumarate occurs exclusively on the hydroxyl group on the γ-carbon of lignin unit side chains, mostly on syringyl units. Although the mechanism of acylation has not been studied directly in these species, it is likely to be similar to that in the Poaceae and involve BAHD acyl-coenzyme A:monolignol transferases.
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Distribution of Fucosylated Xyloglucans among the Walls of Different Cell Types in Monocotyledons Determined by Immunofluorescence Microscopy
Molecular plant, 2010Co-Authors: Maree Brennan, Philip J. HarrisAbstract:Xyloglucans in the non-lignified primary cell walls of different species of Monocotyledons have diverse structures, with widely varying proportions of oligosaccharide units that contain fucosylated side chains (F side chains). To determine whether fucosylated xyloglucans occur in all non-lignified walls in a range of Monocotyledon species, we used immunofluorescence microscopy with the monoclonal antibody CCRC-M1. The epitope of this antibody, α-L-Fucp-(1→2)-β-D-Galp, occurs in F side chains. In most non-commelinid Monocotyledons, the epitope was found in all non-lignified walls. A similar distribution was found in the palm Phoenix canariensis, which is a member of the basal commelinid order Arecales. However, in the other commelinid orders Zingiberales, Commelinales, and Poales, the occurrence of the epitope was restricted, sometimes occurring in only the phloem walls, but often also in walls of other cell types including stomatal guard and subsidiary cells and raphide idioblasts. No epitope was found in the walls of the commelinids Tradescantia virginiana (Commelinaceae, Commelinales) and Zea mays (Poaceae, Poales), but it occurred in the phloem walls of two other Poaceae species, Lolium multiflorum and L. perenne. The distribution of the epitope is discussed in relation to xyloglucan structures in the different taxa. However, the functional significance of the restricted distributions is unknown.
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Xyloglucans of Monocotyledons Have Diverse Structures
Molecular plant, 2009Co-Authors: Yves S.y. Hsieh, Philip J. HarrisAbstract:ABSTRACT Except in the Poaceae, little is known about the structures of the xyloglucans in the primary walls of Monocotyledons. Xyloglucan structures in a range of Monocotyledon species were examined. Wall preparations were isolated, extracted with 6 M sodium hydroxide, and the extracts treated with a xyloglucan-specific endo -(1 → 4)-β-glucanase preparation. The oligosaccharides released were analyzed by high-performance anion-exchange chromatography and by matrix-assisted laser-desorption ionization time-of-flight mass spectrometry. Oligosaccharide profiles of the non-commelinid Monocotyledons were similar to those of most eudicotyledons, indicating the xyloglucans were fucogalactoxyloglucans, with a XXXGa core motif and the fucosylated units XXFG and XLFG. An exception was Lemna minor (Araceae), which yielded no fucosylated oligosaccharides and had both XXXG and XXG n core motifs. Except for the Arecales (palms) and the Dasypogonaceae, which had fucogalactoxyloglucans, the xyloglucans of the commelinid Monocotyledons were structurally different. The Zingiberales and Commelinales had xyloglucans with both XXG n and XXXG core motifs; small proportions of XXFG units, but no XLFG units, were present. In the Poales, the Poaceae had xyloglucans with a XXG n core motif and no fucosylated units. In the other Poales families, some had both XXXG and XXG n core motifs, others had only XXXG; XXFG units were present, but XLFG units were not.
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The range of mobility of the non-cellulosic polysaccharides is similar in primary cell walls with different polysaccharide compositions
Physiologia Plantarum, 1998Co-Authors: Bronwen G Smith, Laurence D Melton, Philip J. Harris, Roger H NewmanAbstract:The molecular mobility of the non-cellulosic polysaccharides in hydrated primary cell walls of three Monocotyledons (Italian ryegrass, pineapple and onion) and one dicotyledon (cabbage) was studied using solid-state 13 C NMR spectroscopy. These cell walls were chosen as they have different non-cellulosic polysaccharide compositions. By exploiting proton rotating-frame and spin-spin relaxation time constants three different cell wall domains which responded to cross-polarization experiments were identified. Most of the non-cellulosic polysaccharides occupied a mobile domain (C), but some occupied a partly rigid domain (B). Crystalline cellulose occupied a highly rigid domain (A). In the cell walls of Italian ryegrass and pineapple, domain C contained mainly glucuronoarabinoxylans and small amounts of rhamnogalacturonans ; domain B contained small amounts of xyloglucans and galacturonans. However, in the cell walls of onion and cabbage, domain C contained mainly rhamnogalacturonans with galactans (in onion) or arabinans (in cabbage) as side chains; domain B contained galacturonans and xyloglucans. Single-pulse excitation was used on Italian ryegrass and cabbage cell walls to reveal signals from a highly mobile fourth domain (D). In Italian ryegrass cell walls domain D contained glucuronoarabinoxylans and small amounts of rhamnogalacturonan, whereas in cabbage cell walls it contained arabinan side chains of rhamnogalacturonans. A novel feature of the research was the use of solid-state 13 C NMR spectroscopy to examine the molecular mobilities of the polysaccharides in Monocotyledon cell walls that contain glucuronoarabinoxylans.
Mathieu Rouard - One of the best experts on this subject based on the ideXlab platform.
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The banana (Musa acuminata) genome and the evolution of Monocotyledonous plants.
Nature, 2012Co-Authors: Angélique D'hont, Olivier Garsmeur, Franc-christophe Baurens, Jean-marc Aury, France Denoeud, Françoise Carreel, Benjamin Noel, Stéphanie Bocs, Gaëtan Droc, Mathieu RouardAbstract:Bananas (Musa spp.), including dessert and cooking types, are giant perennial Monocotyledonous herbs of the order Zingiberales, a sister group to the well-studied Poales, which include cereals. Bananas are vital for food security in many tropical and subtropical countries and the most popular fruit in industrialized countries. The Musa domestication process started some 7,000 years ago in Southeast Asia. It involved hybridizations between diverse species and subspecies, fostered by human migrations, and selection of diploid and triploid seedless, parthenocarpic hybrids thereafter widely dispersed by vegetative propagation. Half of the current production relies on somaclones derived from a single triploid genotype (Cavendish). Pests and diseases have gradually become adapted, representing an imminent danger for global banana production. Here we describe the draft sequence of the 523-megabase genome of a Musa acuminata doubled-haploid genotype, providing a crucial stepping-stone for genetic improvement of banana. We detected three rounds of whole-genome duplications in the Musa lineage, independently of those previously described in the Poales lineage and the one we detected in the Arecales lineage. This first Monocotyledon high-continuity whole-genome sequence reported outside Poales represents an essential bridge for comparative genome analysis in plants. As such, it clarifies commelinid-Monocotyledon phylogenetic relationships, reveals Poaceae-specific features and has led to the discovery of conserved non-coding sequences predating Monocotyledon-eudicotyledon divergence.
David W. Galbraith - One of the best experts on this subject based on the ideXlab platform.
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Nuclear DNA content of Monocotyledons and related taxa
American Journal of Botany, 1994Co-Authors: Geeta Bharathan, Georgina M. Lambert, David W. GalbraithAbstract:Nuclear DNA content of 62 species of angiosperms including 52 Monocotyledons and ten dicotyledons has been estimated by flow cytometry using Nicotiana tabacum var. Xanthi as the internal standard. These data, considered together with previous data on diploid species, suggest the following: 1) Most families and orders of Monocotyledons have small genomes. Contrary to the general impression that Monocotyledons are a group characterized by large genomes, genomes of over 20 pg/2C nucleus occur only in the Liliiflorae, Commelinales, Alismatales, and Araceae. 2) Variation within families ranges from twoto 56-fold, but is twoto fivefold in most families. Thus extraordinary variation in genome size appears to be limited to particular lineages, perhaps owing to some shared feature that facilitates such variation. 3) Endopolyploidy is not observed in the leaves of the species studied, although it has been reported to occur in the roots of several Monocotyledons. This suggests that an examination of the basis for this difference between the roots and leaves of Monocotyledons may provide clues to the mechanisms that regulate endopolyploidization in these organs.
Paula J Rudall - One of the best experts on this subject based on the ideXlab platform.
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Microsporogenesis in Monocotyledons
Annals of Botany, 1999Co-Authors: Carol A Furness, Paula J RudallAbstract:This paper critically reviews the distribution of microsporogenesis types in relation to recent concepts in monocot systematics. Two basic types of microsporogenesis are generally recognized: successive and simultaneous, although intermediates occur. These are characterized by dierences in tetrad morphology, generally tetragonal or tetrahedral, although other forms occur, particularly associated with successive division. Successive microsporogenesis is predominant in Monocotyledons, although the simultaneous type characterizes the ‘lower’ Asparagales. Simultaneous microsporogenesis also occurs in Japonolirion and Petrosaaia (unplaced taxa), some Araceae, Aponogeton, Thalassia and Tofieldia (Alismatales), Dioscorea, Stenomeris and Tacca (Dioscoreales), and some Commelinanae: Arecaceae (Arecales), and Cyperaceae, Juncaceae and Thurniaceae (Poales). Simultaneous microsporogenesis is of phylogenetic significance within some of these groups, for example, Asparagales, Dioscoreales and Poales. An intermediate type is recorded in Stemonaceae (Pandanales), Commelinaceae (Commelinales) and in Eriocaulaceae and Flagellariaceae (Poales). There is little direct relationship between microsporogenesis type and pollen aperture type in monocots (except for trichotomosulcate and pantoporate apertures), although trichotomosulcate apertures in monocot pollen, and equatorial tricolpate and tricolporate apertures in eudicot pollen, are all related to simultaneous microsporogenesis. # 1999 Annals of Botany Company
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Inaperturate Pollen in Monocotyledons
International Journal of Plant Sciences, 1999Co-Authors: Carol A Furness, Paula J RudallAbstract:Inaperturate pollen is widespread in the Monocotyledons, includes a diverse range of forms, and has arisen independently numerous times. Evidence for this comes from the phylogenetic distribution of inaperturate pollen and also from developmental and structural differences. There is no correlation between the production of inaperturate grains and either microsporogenesis type or tapetum type. Inaperturate pollen has phylogenetic significance within some groups, e.g., in Zingiberales, Liliales, and some Asparagales. Character states for inaperturate pollen are presented. It can broadly be divided into two types, “omniaperturate” and “functionally monoaperturate,” based on the thickening of the intine. The characters of omniaperturate pollen are adaptations that potentially increase the germination efficiency of the pollen. Both types sometimes occur in environments where pollen is not subject to desiccation and, thus, may remain viable with reduced exines.
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Calcium Oxalate Crystals in Monocotyledons: A Review of their Structure and Systematics
Annals of Botany, 1999Co-Authors: Christina J. Prychid, Paula J RudallAbstract:Abstract Three main types of calcium oxalate crystal occur in Monocotyledons: raphides, styloids and druses, although intermediates are sometimes recorded. The presence or absence of the different crystal types may represent ‘useful’ taxonomic characters. For instance, styloids are characteristic of some families of Asparagales, notably Iridaceae, where raphides are entirely absent. The presence of styloids is therefore a synapomorphy for some families (e.g. Iridaceae) or groups of families (e.g. Philydraceae, Pontederiaceae and Haemodoraceae). This paper reviews and presents new data on the occurrence of these crystal types, with respect to current systematic investigations on the Monocotyledons.
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The Nucellus and Chalaza in Monocotyledons: Structure and systematics
The Botanical Review, 1997Co-Authors: Paula J RudallAbstract:The majority of Monocotyledons are crassinucellate, including some early-branching taxa (sensu Chase et al., 1995a, 1995b) such asTofieldia, although Araceae are predominantly tenuinucellate. The tenuinucellate condition occurs in a taxonomically wide range of Monocotyledons, and there is some congruence between this character and existing monocot topologies at higher levels. For example, present evidence indicates a few tenuinucellate asparagoid clades, including Alliaceae sensu stricto and Hypoxidaceae, possibly two tenuinucellate lilioid lineages, and at least two tenuinucellate commelinoid lineages.
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Lateral Meristems and Stem Thickening Growth in Monocotyledons
The Botanical Review, 1991Co-Authors: Paula J RudallAbstract:Although Monocotyledons lack a vascular cambium of the type found in dicotyledons and conifers, lateral meristems still play an important role in the establishment of their growth habits. The presence near the shoot apex of a primary thickening meristem (PTM), which is probably plesiomorphic in Monocotyledons, predisposes evolution into the many pachycaul forms. A PTM occurs in virtually all Monocotyledons, whereas the secondary thickening meristem (STM), which is morphologically similar, is limited to a few genera of Liliiflorae. these records are reviewed in a systematic context. To a greater or lesser extent in different taxa, the PTM is responsible for primary stem thickening, adventitious root production, and formation of linkages between stem, root and leaf vasculature. The STM largely contributes to the body of the stem. The sometimes obscure distinction between the two meristems, and their relationship with other stem meristems are discussed. For systematic purposes stem thickening in Monocotyledons is separated into two characters: diffuse growth (as in palms), and growth by means of lateral meristems. The three states of the second character are represented by the first three of Mangin’s (1882) four categories (two herbaceous, the third arborescent): (1) The lateral meristem is limited in extent, and ceases activity after root formation. (2) It remains active for a limited period after cessation of root formation, contributing to the plant body. (3) It remains active throughout the life of the plant, contributing the bulk of the plant body.
Hans Lambers - One of the best experts on this subject based on the ideXlab platform.
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summer dormancy and winter growth root survival strategy in a perennial Monocotyledon
New Phytologist, 2009Co-Authors: Michael W Shane, John S Pate, Margaret E Mccully, Martin J Canny, Ulrike Mathesius, Gregory R Cawthray, Hans LambersAbstract:Summary • Here, we tested the alternation of root summer dormancy and winter growth as a critical survival strategy for a long-lived Monocotyledon (Restionaceae) adapted to harsh seasonal extremes of Mediterranean southwest Western Australia. • Measurements of growth and the results of comparative studies of the physiology, water content, metabolites, osmotic adjustments, and proteomics of the dormant and growing perennial roots of Lyginia barbata (Restionaceae) were assessed in field-grown plants. • Formation of dormant roots occurred before the onset of summer extremes. They resumed growth (average 2.3 mm d−1) the following winter to eventually reach depths of 2–4 m. Compared with winter-growing roots, summer dormant roots had decreased respiration and protein concentration and c. 70% water content, sustained by sand-sheaths, osmotic adjustment and presumably hydraulic redistribution. Concentrations of compatible solutes (e.g. sucrose and proline) were significantly greater during dormancy, presumably mitigating the effects of heat and drought. Fifteen root proteins showed differential abundance and were correlated with either winter growth or summer dormancy. None matched currently available libraries. • The specific features of the root dormancy strategy of L. barbata revealed in this study are likely to be important to understanding similar behaviour in roots of many long-lived Monocotyledons, including overwintering and oversummering crop species.