Cell wall architectures in fibre crops

Transcription

1 Cell wall architectures in fibre crops B Chabbert, UMR FARE, Reims Multihemp Lille

2 Plant fibers 2

3 Plant fibers variability: botanical origin Fiber sources Anatomical features Wood Pine Poplar gymnosperms dicot Cambium Tracheids Fibers, vessels Stem uter tissues Flax, Hemp Kenaf, Jute Dicot Procambium Sclerenchyma Inner tissues Cambium Fibers, vessels Straw Bagasse Miscanthus Monocot Procambium Leave Sisal, abaca Monocot Procambium Vascular bundle Fibers, vessels, Seed (trichomes) Coton Dicot Epidermis Fibres 3

4 Plant fibers = lignocellulosic cell walls Polysaccharides Phenols Proteins Pectins Hemicellulose Cellulose Lignin Glycoproteins Common chemical characteristics Large range in content and composition of each polymer Minerals Extractibles Water 4

5 Morphology and chemical composition Xylem fibers short fibers Sclerenchyma long fibers Length (mm) Cellulose % Lignin % Non cellulosic polysaccharides % Flax (sclérenchyme) Harwood Softwood

6 Plant fibers = lignocellulosic cell walls S3 S3 S2 S2 S1 S1 Complex composite material showing hierarchical and multilayered structure Secondary wall Cellulose /hemicellulose/ lignin Primary wall Cellulose-hemicellulose/pectin-lignin Fiber tracheid Mass % cellulose hemicellulose lignin Primary CW Middle lamella Hemicellulose/pectin-lignine Chemical gradient S S S Gibson,

7 Cell wall chemical gradient Cell wall formation: spatio-temporal controlled biological events and polymer assembly (environmental x genetic control) ML PI S1 PII S2 Cellulose Pectins Hemicelluloses Lignin S3 ML: middle lamella; PI primary CW ; PII, Secondary cell wall 7

8 Cell wall architecture Polymer assembly : composite structure Chundawat et al., 2011 Cellulosic frame embedded in an amorphous matrix Interactions between cellulose-matrix and between matrix polymers 8

9 Fiber architecture Polymer content, structure, composition and interactions Wet chemistry (fibres et polymères extraits) Spectroscopy (NMR, Infrared, Raman ) Microscopy, topochemistry (immuno)cytochemistry microspectroscopies IR, fluorescence, Raman ) Nanoscale microscopies ( TEM, FE-SEM, AFM /nanoir, Surface force.) Changes induced by physico,-chemical, thermomechanical, enzymatic treatments Mechanical properties, water sorption 9

10 Cell-wall variability in fiber crops at tissue/cell level Hemp, Flax Bast fibers 2-5 % lignin Core xylem % lignin 10

11 Cellulose: load bearing polymer Plant fibers mostly secondary walls Cristalline cellulose Secondary cell wall : multilayer structure Distinct microfibril orientation in S1/S1 and S3 Cellulose structure: Cristallinity Polymerisation degree Morvan, 2005; Salmen, Bergstrom,

12 Fiber tensile properties: main contribution of cellulose Microtensile test of fiber bundles or single fiber) Nanoindentation test on secondary cell walls - Tensile stiffness of the secondary walls is related to the microfibril angle (higher MFA/lower stiffness) - Load-bearing capacity of cellulose fibrils Burgert and Keplinger,

13 Cristalline cellulose, main component of hemp and flax fibers Highly orientated cellulose Microfibril angle 6 10 X ray diffraction Primary fibers Cristal size (A) Cr.I. D (101) D (10-1) D (002) Flax Hemp Bonatti et al, 2004; Mellerowic,

14 Bast fibers in hemp and flax: cellulose-rich fibers hemp ep Bf1I Primary fibers (Bf1) Flax Bf 2 Secondary fibers (Bf2) Bf 1 50 µm Hemp Flax Length, mm Diameter, µm Cellulose (%) Cristallinity Non cellulosic polysaccharides % Lignin, %

15 Bast fibers properties Scattering of mechanical properties (cellulose and amorphous polymers) Marrot et al,

16 Cell-wall amorphous polymers: Non cellulosic polysaccharides - Lignin 16

17 CW amorphous polymers: Non cellulosic polysaccharides - Lignin Vogel et al,

18 Cell-wall variability in fiber crops at tissue/cell level Hemp, Flax Bast fibers 2-5 % lignin Core xylem % lignin 18

19 CW amorphous polymers: Primary cell walls Pectin Homogalacturonans Rhamnogalacturonans decorated by galactans (RGI) and complex side chians (RG II) RG I HG RG II Arabinogalactan protein (arabinogalactan proteins) protein Lignin (phenol polymer) main lignin monomers CH 2 CH 2 Hemicellulose Xyloglucan H CH 3 H 3 C CH 3 bast fiber xylem Ralph, 2007; Morvan et al, 2004; Mellerowitz and Gorshkova 2013; Pauly et al,

20 Primary cell wall architecture Simmons et al, 2010; Cosgrove and Jarvis, 2012; Cosgrove,

21 CW amorphous polymers: Secondary cell walls of bast fibers Pectins (Rhamnogalacturonans decorated by galactans,) RG I galactan Hemicellulose Mannan Arabinogalactan protein Secondary cell wall architecture - Non covalent interactions cellulose/ non cellulosic matrix (galactan, mannan) AGP (3,6) galactan glucomannan (1,4) galactan - Covalent and non covalent interactions between matrix polymers RG I Morvan et al, 2004, Tan et al 2010; Mellerowitz and Gorshkova

22 Network pectin- protein- hemicellulose Tan et al,

23 Secondary cell walls: bast fibers Transmission electron microscopy S2 S1 P1 Thuault et al, 2015 Thick secondary cell walls show concentric S2 sublayers Thuault et al, 2015 Scanning electron microscopy 23

24 CW amorphous polymers: Secondary cell walls of core xylem Hemicellulose Glucuronoxylan Lignin Mannan Secondary cell wall architecture Terashima et al, 2009; Pauly et al, 2013, Mellerowitz and Gorshkova 2013, Jin et al,

25 Covalent interactions lignin hemicelluloses Lignin carbohydrate complex (LCC) Lawoko,

26 Branched domain Linear domain G lignin CH 2 mixed S/G lignin CH 2 CH 2 H CH 3 Guaiacyl H CH 3 H 3 C CH 3 Guaiacyl Syringyl Ralph et al,

27 Lignin carbohydrate complex (LCC) CH Lignin H Me H H 3 C H Lignin CH 3 H 3 C H 3 C H H CH 3 CH 3 CH 3 Me H CH 3 Me H Xylan Me H Me H H 3 C CH 3 CH 3 CH 2 Glucomannan H H H CH 3 CH 3 Lignin-xylan Me Me H H 3 C H H 3 C CH 3 H H H CH 3 CH 3 H 3 C H 3 C CH 3 CH 3 Lignin Lignin-glucomannan H 3 C Lignin H H 3 C CH 3 Gellerstedt,

28 Lignified core xylem S2 300 nm Lignin removal S2 surface (formation) Terashima et al, 2004;

29 Lignin/polysaccharide networks Middle lamella (cell corner) LCC globular organization Secondary CW (S2) LCC organization linked to microfibril orientation Terashima et al

30 Nanoscale mapping of CW Atomic Force Microscopy (AFM), Scanning Near field ptical Microscopy (SNM) Lignin cellulose Bioinspired lignocellulosic assemblies nm AFM SNM cellulose-lignin 1.0µm 0.00 nm AFM cellulose-hemicellulose-lignin Keplinger et al, 2015; Hambardzumyan et al, 2014, Muraille et al submitted 30

31 CW architectures of fiber crops Plant Transformations rgan Macro Fiber extraction, process, Tissue Cell Micro T, water, chemical biological agents Cell wall Polymer assembly Network Polymer 31