Table 1.

Summary of the available studies on fibre crops addressing transcriptomics, metabolomics or proteomics.

Species	Type of study	Tissue(s)	Relevant results	Reference
L. usitatissimum	histology, GC-analysis	inner and outer stem tissues	different pattern of laccase-gold particles detected in stem tissues which relates to phenolic compounds	[75]
L. usitatissimum	histochemistry/chemical analysis	bast fibres at 2 developmental stages	xylem and bast fibres rich in G units, H units present in bast fibres	[76]
L. usitatissimum	ESTs from cDNA library/RT-PCR	outer stem tissue	highly expressed cell wall-related ESTs found: CesAs, XTH, peroxidase, β-xylosidase and β-galactosidase	[77]
C. sativa	microscopy/chemical analysis	bast fibres from apical and basal regions of the stem	condensed lignin in stem, p-hydroxyphenyl units decline with maturity	[78]
C. sativa	cDNA microarray/qPCR	outer stem tissue top, middle, bottom	GT transcripts enriched in the middle and bottom regions, GH transcripts enriched in the top region; top region rich in PRPs; middle and bottom regions rich in AGPs	[79]
L. usitatissimum	cDNA library	fibre-bearing phloem tissues from stem/3 segments along stem axis	AGP, LTP enriched in elongation and cell wall-thickening regions; chitinases, β-galactosidases enriched also in specific stages of stem development	[80]
C. sativa	cDNA microarray/lignin histochemistry/chemical analysis/Northern blot	wooden core vs. bast fibres in the top, middle, bottom regions	upregulation of PP and shikimate pathways, AAA and lignin biosynthesis, C1 metabolism in the core tissue; AGPs, genes in lipid/wax metabolism and photosynthesis upregulated in bast tissues	[81]
L. usitatissimum	histology, 2D-DIGE	isolated fibres, cortical tissue	enrichment of β-galactosidase, rhamnose biosynthetic enzyme	[82]
L. usitatissimum	cDNA microarray/qPCR/activity staining	hypocotyls at 7, 9 and 15 days	genes involved in primary wall deposition upregulated in the early stage, AGPS and β-galactosidase expressed in the middle stage, secondary metabolism and GH transcripts upregulated in the last stage	[83]
L. usitatissimum	454 sequencing of high-density oligo-microarray/qPCR	different tissues and cultivars (Drakkar vs. Belinka)	secondary metabolism-associated genes highly represented in stems; 3 FLAs, laccases overexpressed in core tissue; 3 FLAs overexpressed in outer stem tissue; 6 LTPs, lipid/wax metabolism and photosynthesis-associated genes overexpressed in outer tissue; cultivars differ in cell wall- and biotic stress response-related genes	[84]
L. usitatissimum	cDNA library	bark	21 cell wall-related ESTs and C2H2 transcription factors identified	[85]
L. usitatissimum	lignomics/microarray	inner and outer stem tissues	hypolignification associated with low abundance of monolignol biosynthetic genes, 81 phenolic compounds found, 65 identified for the first time, lignan-associated genes abundant in inner tissues	[86]
L. usitatissimum	miRNA	bottom leaves, stem, leafless apex	20 miRNA identified, which could regulate cell wall metabolism	[87]
L. usitatissimum	Cell wall proteome, 1D-PAGE, MALDI-TOF	isolated fibres	List of potential cell wall proteins of flax fibres	[88]
L. usitatissimum	Cell wall proteome, LC-MS/MS	Cortical tissue, cell wall protein enrichment	Identification of > 150 predicted cell wall proteins, major group acting on sugars and glycoproteins	[89]
B. nivea	Illumina paired-end sequencing	xylem, shoot, leaves, bark from seedlings, 30- and 60-days old plants	51 genes of the CesA superfamily identified, 36 showing high expression in bark	[90]

List of abbreviations used: CesAs: cellulose synthase; XTH: xyloglucan endotransglycosylase/hydrolase; GT: glycosyltransferase; GH: glycosylhydrolase; PRPs: proline-rich proteins; AGPs: arabinogalactan proteins; PP: pentose phosphate; AAA: aromatic aminoacids; FLAs: fasciclin-like arabinogalactan proteins; LTP: lipid-transfer protein.