Table 1.

List of the genes and mutant phenotypes described

Name	Mutant	Mutant phenotype	Reference
AtCESA1	rsw1, any1, fxr2	Reduced cellulose content in primary cell walls, reduced growth, radial cell swelling (rsw1) Reduced growth, swollen roots, bulging epidermal cells in cotyledons and reduced crystalline cellulose content (any1) Resistance to flupoxam, smaller rosettes and reduced crystalline cellulose (fxr2). CESA1 null mutants are lethal	[22, 271, 272]
AtCESA2	cesa2	Phenotypically normal. CESA2 overexpression in cesa6 null mutants can rescue to some extent the cesa6-dependent growth defects	[20]
AtCESA3	cev1, eli1, ixr1	Seedlings exhibit constitutive JA and ET accumulation, reductions in cellulose levels, are smaller and have roots thicker than wt (cev1) Reduced plant growth, ectopic lignification and reduced cellulose content in seedlings (eli1) ixr1 plants are phenotypically normal, exhibit slight reductions in crystalline cellulose levels and resistance to ISX	[22–24, 26]
AtCESA4	irx5	Reduced cellulose levels in secondary cell walls. Defects in cell wall thickness in xylem vessels. Reduced mechanical strength of the stems. Adult plants are smaller than wt	[273]
AtCESA5	cesa5	Mutant plants exhibit defective seed coat mucilage synthesis. CESA5 overexpression in cesa6 null mutants can rescue partially cesa6-dependent growth defects	[20]
AtCESA6	prc1, ixr2	Defects in cellulose production during primary cell wall formation, short hypocotyls and ectopic lignification (prc1) No obvious growth phenotypes but ISX resistant (ixr2)	[23, 274, 275]
AtCESA7	irx3	Reduced cellulose levels in secondary cell walls. Defects in cell wall thickness in xylem vessels. Reduced mechanical strength of the stems. Adult plants are smaller than wt	[13]
AtCESA8	irx1	Reduced cellulose in secondary cell walls. Defects in cell wall thickness in xylem vessels. Reduced mechanical strength of the stems. Adult plants are smaller than wt	[15]
AtCESA9	cesa9	Mutant plants display wt-like phenotype. Epidermal cells in seed coats of cesa9 seeds are distorted	[276]
AtCESA10	cesa10	No obvious mutant phenotypes	[17, 18]
KORRIGAN	kor1	Dwarf, cellulose deficient, display defects during cytokinesis	[47, 277]
KOBITO	kob1	Dwarf, sterile, short hypocotyls, incomplete cell wall during cytokinesis, cellulose deficient	[48]
CHITINASE-LIKE 1	ctl1/pom-pom1	Cellulose deficient, the mutation affects xyloglucan structure. Mutant plants are smaller than wt, have shorter hypocotyls and swollen roots. ctl1 phenotype is rescued by overexpressing CTL2	[49, 52]
CHITINASE-LIKE 2	ctl2	Mutant plants are similar to the wt but display ectopic lignification in stems and etiolated hypocotyls	[49]
CELLULOSE SYNTHASE INTERACTING1	csi1/pom-pom2	Dwarf, short hypocotyls, swollen cells, altered microtubule organization and cellulose deficient	[52, 278]
MUNC13-LIKE PROTEIN	patrol1	Cellulose deficient, mutants are smaller than wt. This mutant displays short hypocotyls and roots. Adult plants are significantly smaller than the wt	[32, 279]
STELLO1	stl1	No obvious mutant growth phenotype. Functionally redundant with STL2	[34]
STELLO2	stl2	No obvious mutant growth phenotype. Functionally redundant with STL1, double stl1stl2 mutants are small, display cellulose deficiency and reduced cell wall thickness	[34]
KINESIN-LIKE PROTEIN	fra1	Dwarf plants with reduced mechanical strength. Mutant plants display changes in cellulose orientation with no overall reduction of cellulose	[45]
CELLULOSE SYNTHASE-LIKE PROTEIN D2	csld2	Root hair formation defective with altered cytoskeleton organization	[258]
CELLULOSE SYNTHASE-LIKE PROTEIN D3	csld3/kjk	Root hair formation defective resulting in root hair rupture	[74, 258]
CELLULOSE SYNTHASE-LIKE PROTEIN D5	csld5	No obvious growth phenotype, required for cell plate formation	[75, 280]
CELLULOSE SYNTHASE-LIKE PROTEIN A7	csla7	Pollen tube growth defects and embryogenesis failure. Overexpression of CSLA9 rescues csla7 mutant phenotype	[80]
CELLULOSE SYNTHASE-LIKE PROTEIN A9	csla9	Reduced glucomannan. No obvious mutant phenotypes	[79, 80]
XYG-XYLOSYLTRANSFERASE	xxt1	No obvious mutant phenotypes	[105]
XYG-XYLOSYLTRANSFERASE	xxt2	No obvious mutant growth phenotypes. Double xxt1 xxt2 show smaller rosettes and collapsed stems. Seedling hypocotyls are smaller and thicker than the wt. Cellulose deficiency associated with cellulose fibril and cortical microtubules disorganization. Lack detectable xyloglucan	[105, 281]
XYLOGLUCAN GALACTOSYLTRANSFERASE	mur3-3	Cabbage-like phenotype, smaller plants with smaller rosettes. Altered xyloglucan composition. MUR3-dependent phenotype can be rescued by knocking out XXT2 alone or together with XXT1	[107, 111]
FUCOSYLTRANSFERASE 1	mur2	No obvious mutant growth phenotype, impaired in xyloglucan fucosylation	[172, 282, 283]
PUTATIVE FAMILY 43 GLYCOSYL TRANSFERASE	irx9	Irregular xylem phenotype, reduced cell wall thickness due to xylan chain elongation defects. Reduced xylose levels	[267]
PUTATIVE FAMILY 43 GLYCOSYL TRANSFERASE	irx9-like	No obvious mutant phenotypes	[124]
PUTATIVE FAMILY 43 GLYCOSYL TRANSFERASE	irx14	Slightly smaller plants, with thinner vessels. Reduced xylose levels	[123, 124]
PUTATIVE FAMILY 43 GLYCOSYL TRANSFERASE	irx14-like	No obvious mutant phenotypes	[123]
PUTATIVE FAMILY 47 GLYCOSYL TRANSFERASE	irx10	Overall normal plants with reduced xylose levels associated with a mild irregular xylem phenotype	[127]
PUTATIVE FAMILY 47 GLYCOSYL TRANSFERASE	irx10-like	No obvious mutant phenotypes	[127]
GLUCURONYL TRANSFERASE	gux1	No obvious mutant growth phenotype. Significantly reduced levels of GlcA-substituted xylan	[284]
GLUCURONYL TRANSFERASE	gux2	No obvious mutant phenotype. Significantly reduced levels of GlcA-substituted xylan. Double gux1/gux2 mutants lack almost all detectable xylan substitutions	[125, 284]
GLUCURONYLTRANSFERASE	gux3	No obvious mutant growth phenotype. Significantly reduced levels of GlcA-substituted xylan. Triple gux1gux2 gux3 mutants are small and have reduced resistance to breaking force	[133]
GLUCURONOXYLAN-METHYLTRANSERASE	gxmt1-1	No obvious mutant growth phenotype. Reduced methylation of glucuronoxylan	[138]
GALACTURONOSYLTRANSFERASE 1-GAUT 8	qua1/gaut8	Significantly reduced growth and decrease in both HG and xylan-synthase activity	[159]
GALACTURONOSYLTRANSFERASE 10-GAUT 10	gaut10	Mutant seedlings exhibit growth defects and short roots in the absence of sucrose	[162]
GALACTURONOSYLTRANSFERASE 11-GAUT 11	gaut11	Identified as HG α-GalA transferase. KO mutant seeds produce less RG I and mucilage in coat epidermal cells (SCE)	[167]
PUTATIVE GLYCOSYLTRANSFERASE	muci70	Required for pectin synthesis in seed coat epidermal cells. KO mutant seeds produce less mucilage	[167]
PUTATIVE METHYLTRANSFERASE	qua2	Defective in cell adhesion, characterized by reduced HG content	[285]
PUTATIVE HOMOGALACTURONAN-METHYLTRANSFERASE	qua3	No obvious growth defects and normal pectin methylation in KO plants. QUA3 RNAi suspension cells exhibit reduced pectin methylation	[156]
PECTIN METHYLTRANSFERASE-CGR2	cgr2	No obvious mutant growth phenotype. Slight reduction in uronic acids and pectin methylation	[161]
PECTIN METHYLTRANSFERASE- CGR3	cgr3	No obvious growth phenotypes. cgr2 cgr3 plants are dwarf, display reduced cell elongation. Double mutant plants show significant reduced degree of methylesterification, and uronic acids content compared to the single mutants, in addition to a slight cellulose reduction	[161]
XYLOGALACTURONAN-XYLOSYLTRANSFERASE	xgd1	No obvious mutant growth phenotype. Reduced xylose levels associated with a reduction in xylogalacturonan content	[163]
GOLGI GDP-l-GALACTOSE TRANSPORTER1	gglt1/gonst3	Mutant growth phenotype is rescued by application of boric acid. Mutant lines exhibit reduced levels of L-galactose in side-chain A of RG-II	[171]
GDP-MANNOSE 4,6 DEHYDRATASE ACTIVITY	mur1	KO plants are defective in L-fucose, content in both pectin and hemicellulose. Reduced strength to mechanical force. Phenotype can be rescued by boric acid application	[171, 173]
GALACTAN SYNTHASE 1	gals1	No obvious mutant growth phenotype. KO plants display decreased β-1,4-galactan content. Reduced galactose in stems. Decreased galactose in seeds	[164]
GALACTAN SYNTHASE 2	gals2	No obvious mutant growth phenotype but decreased β-1,4-galactan content. Decreased galactose levels in seeds	[164]
GALACTAN SYNTHASE 3	gals3	No obvious mutant growth phenotype. Mutant plants display decreased β-1,4-galactan content. Reduced galactose in stems	[164]
RHAMNOGALACTURONAN-II XYLOSYLTRANSFERASE-1	rgxt1	No obvious mutant growth phenotype. Involved in the xylosylation of the internal fucose moiety RG II	[168]
RHAMNOGALACTURONAN-II XYLOSYLTRANSFERASE-2	rgxt2	No obvious mutant growth phenotype. Involved in the xylosylation of the internal fucose moiety RG II	[168]
RHAMNOGALACTURONAN-II XYLOSYLTRANSFERASE-3	rgxt4/mgp4	Short siliques. KO plants are impaired in pollen tube growth	[170]
O-ACETYLTRANSFERASE	rwa2	No obvious mutant growth phenotype. KO plants characterized by reduced wall acetylation of both pectic and non-pectic polysaccharides. KO plants show increase resistance to B.cinerea	[142]
O-ACETYLTRANSFERASE	tbl10	No obvious mutant growth phenotype. KO plants show reduced RG I acetylation and enhanced drought stress resistance	[175]
O-ACETYLTRANSFERASE	tbl44/pmr5	KO plants show reduced rosette size. Enhanced resistance to powdery mildew and C. higginsianum. KO plants exhibit reduced pectin methyl esterification/O-acetylation associated with increased amount of pectins	[151, 177]
MURUS8	mur8	KO plants have no obvious mutant growth phenotype but exhibit reductions in rhamnogalacturonan-I and rhamnose content as well as enhanced resistance to C. higginsianum	[151, 179, 282]
PECTIN METHYLESTERASE 5	pme5	Involved in regulating HG methylesterification in stems. PME5 expression is reduced in the internodes of blr-6 mutants leading to reduced cell expansion and internode elongation	[286]
PECTIN METHYLESTERASE INHIBITOR 3	pmei3	Involved in regulating pectin de-metylesterification in apical meristems. PMEI3 overexpression inhibits primordial formation	[287]
PECTIN METHYLESTERASE 35	pme35	KO plants exhibit reduced mechanical strength in the basal part of the inflorescence stems. Reduced cell wall thickness in cortical cells of mature stems, possibly due to changes HG de-methylesterification	[190]
RECEPTOR-LIKE PROTEIN 44	rlp44/cnu2	Adult KO plants exhibit stunted growth, reduced petiole length and rosette diameter. Mutant seedlings show reduced root and hypocotyl length in high sucrose levels as well as salt oversensitivity	[192]
WALL-ASSOCIATED KINASE 1	wak1	No obvious mutant growth phenotype. WAK1 overexpression leads to enhance callose deposition in response to wounding and exogenous OG application. WAK1 overexpression is associated with enhanced B. cinerea resistance	[288]
WALL-ASSOCIATED KINASE 2	wak2	In the absence of sucrose wak2 KO seedlings are characterized by stunted growth and short roots. Exogenous application of metabolic active sugars (fructose or glucose) helps in rescuing WAK2-dependent cell elongation defects	[152]
OsCESA7 (rice)	S1-24	Smaller rice plants with brittle culm phenotype. Reduced resistance to mechanical force and cellulose deficient	[63]
OsCESA4 (rice)	brittle culm7/bc7(t)	Cellulose reduction and overall fragility of the mutant plants. Cellulose reduction is associated to enhanced lignin accumulation in stems and leaves	[289]
COBRA-like protein (rice)	brittle culm1	Cellulose deficient enhanced lignification and reduced resistance to mechanical force associated to brittle culm phenotype. Exhibit reduced leaf elongation	[66]
COBRA-like protein—(rice)	brittle culm5	Brittle culm phenotype, reduced lignification of the nodes. Cellulose and glucuronosyl arabinoxylan deficient	[64]
GA20-oxidase (Sorghum)	dwf1-1	Cellulose deficient mutant, dramatically reduced growth, gibberellin synthesis impaired. This mutation affects the expression of Sorghum CESA1, 3 and 6	[290]
Cellulose synthase-like F6 (rice)	cslF6	Reduced plant height and smaller stems. Impaired in MLG synthesis	[89]
KINESIN-LIKE PROTEIN (rice)	brittle culm 12	Dramatically reduced growth, with short roots and internodes. Culms display brittle phenotype with reduced cell wall strength	[68]
GLYCOSYLTRANSFERASE FAMILY 61(rice)	xax1	Mutant plants exhibit reduced growth. Xylose-deficient loss-of-function rice mutant. xax1 plants are deficient in ferulic and coumaric acid	[269]
PECTIN ACETYLESTERASE1 (black cottonwood)	PtPAE1	Overexpression in tobacco leads to reduction in acetyl groups of pectins	[182]
GALACTURONOSYLTRANSFERASE 4 (switchgrass, poplar)	KD-GAUT4 (RNAi) gaut4	Involved in the synthesis of HG. Reduced expression of GAUT4 in switchgrass and poplar associated with reduced HG and RG II content. KD transgenic plants show enhanced growth when compared to wt plants	[202]
POLYGALACTURONASE 1 β SUBUNIT	OE:OsBURP16	Rice plants overexpressing BURP16 are phenotypically normal. At cellular level oeOsBURP16 transgenic plants show reduced cell adhesion and reduced resistance to breaking force	[207]