Table 1.

Role of ascorbate in plant growth and development and abiotic stress tolerance

Enzyme/protein	Target plant	Gene	Gene source	Type of genetic manipulation	Ascorbate content	Phenotypic changes	Reference
GDP-mannose pyrophosphorylase	Tobacco	GMPase	Tomato	Overexpression	2.0–4.0-fold increase	Increased tolerance to temperature stress	Wang et al. 2011
Phosphomannose Isomerase	Arabidopsis	PMI1	Arabidopsis	RNAi	0.47–0.65-fold decrease	No phenotypic changes under normal growth conditions in both mutants	Maruta et al. 2008
		PMI2	–	T-DNA knockout	No change
Phosphomannomutase	Tobacco	NbPMM	Tobacco	VIGS	Up to 3.0-fold decrease	–	Qian et al. 2007
	Arabidopsis	NbPMM	Tobacco	VVMEE	0.2–0.5-fold increase	–
		AtPMM	Arabidopsis	Overexpression	0.25–0.33-fold increase	Increased tolerance to MV stress
	Tobacco	PMM	Acerola	Overexpression	2.0-fold increase	–	Badejo et al. 2009
VTC4/Myoinositol monophosphatase (IMP)	Arabidopsis	VTC4	–	T-DNA knockout	0.61–0.75-fold decrease	22.4% –34% decreases in myoinositol content	Torabinejad et al. 2009
						Slow seed germination under control conditions
						Slightly hypersensitive to ABA and NaCl during seed germination
GDP-L-galactose phosphorylase	Arabidopsis	vtc5-1 and vtc5-2	Arabidopsis	T-DNA knockout	0.2-fold decrease	Plant growth retardation and bleaching of the cotyledons	Dowdle et al. 2007
L-Galactose dehydrogenase	Tobacco (BY–2 cells)	L–GalLDH	Tobacco	Overexpression	1.5–2.0-fold increase	Higher mitotic index in cells	Tokunaga et al. 2005
						Reduced browning and cells death of cultures
						Increased tolerance to MV
L-galactono-1,4-lactone dehydrogenase	Tobacco (BY–2 cells)	GLDH	Tobacco	Antisense downregulation	0.30-fold decrease	Adversely effected plant cell division, growth and structure of plant cell	Tabata et al. 2001
	Tobacco	RrGalLDH	Rosa roxburghii	Overexpression	2.1-fold increase	Enhanced tolerance to salt stress	Liu et al. 2013a
Monodehydroascorbate reductase	Tobacco	AtMDAR1	Arabidopsis	Overexpression	Up to 2.2-fold increase	Enhanced tolerance to ozone, salt and PEG stresses	Eltayeb et al. 2007
	Tobacco	Am-MDAR	Avicennia marina	Overexpression	Up to 2.0-fold increase	Increased tolerance to salt stress	Kavitha et al. 2010
	Tobacco	MDAR-OX	Arabidopsis	Overexpression	Up to 1.1-fold increase	No change in Aluminium tolerance	Yin et al. 2010
Dehydroascorbate reductase	Tobacco	DHAR-OX	Arabidopsis	Overexpression	Up to 1.3-fold increase	Increased tolerance to Al stress	Yin et al. 2010
	Tobacco	DHAR	Arabidopsis	Overexpression	1.9–2.1-fold increase	Enhanced tolerance to ozone, drought and salinity	Eltayeb et al. 2006
	Tobacco	DHAR	Wheat	Overexpression	2.1-fold increase	Increased ozone tolerance and NPR	Chen and Gallie 2005
			Tobacco	Antisense downregulation	0. 29-fold decrease	Substantially reduced stomatal area and low NPR
	Tobacco	DHAR	Human	Overexpression	No significant change	Enhanced tolerance to low temperature and NaCl	Kwon et al. 2003
Ascorbate peroxidase	Tobacco	tAPx	Tobacco	Overexpression	No change	Increased tolerance to MV and chilling stresses under light conditions	Yabuta et al. 2002
			Tobacco/ Spinach	Antisense downregulation	–	Plants failed to grow
	Arabidopsis	HvAPX1	Barley	Overexpression	–	Increased tolerance to salt stress	Xu et al. 2008
	Arabidopsis	OsAPXa and OsAPXb	Rice	Overexpression	–	Increased tolerance to salt stress	Lu et al. 2007
	Tobacco	CAPOA1	Pepper	Overexpression	–	Increased plant growth	Sarowar et al. 2005
						Increased tolerance to MV stress
	Tobacco BY-2 cells	cAPX	Arabidopsis	Antisense downregulation	No change	Increased tolerance against heat and salt stresses	Ishikawa et al. 2005
	Tobacco	StAPX	Tomato	Overexpression	–	Improved seed germination	Sun et al. 2010a
						Increased tolerance to salt and osmotic stresses
	Rice	Apx1/ Apx2	Rice	RNAi (Apx1+ Apx2)	Up to 1.5-fold decrease	No change in plant growth and development	Rosa et al. 2010
						Increased tolerance to aluminium
				RNAi (Apx1 or Apx2)	–	Produced semi-dwarf phenotype
	Rice	OsAPx-R	Rice	RNAi	–	Delayed plant development	Lazzarotto et al. 2011
	Rice	OsAPXa	Rice	Overexpression	–	Increased spikelet fertility under cold stress	Sato et al. 2011
	Rice	Osapx2	Rice	Overexpression	–	Enhanced stress tolerance	Zhang et al. 2013
						Sensitive to abiotic stresses
			–	T-DNA knockout	–	Semi-dwarf seedlings, yellow-green leaves, leaf lesion-mimic and seed sterility
	Alfalfa	Osapx2	Rice	Overexpression	–	Increased salt resistance	Guan et al. 2012
	Tomato	cAPX	Pea	Overexpression	–	Enhanced tolerance to UV-B and heat stresses	Wang et al. 2006
	Tomato	cAPX	Pea	Overexpression	–	Enhanced tolerance to chilling and salt stresses	Wang et al. 2005
	Tomato	LetAPX	Tomato	Antisense downregulation	No significant change	Transgenic plants photosynthetically less efficient and sensitive to chilling stress	Duan et al. 2012b
Ascorbate oxidase	Tobacco	AAO	Cucumber	Overexpression	No change	Plants become susceptible to ozone	Sanmartin et al. 2003
	Tobacco	AAO	Cucumber	Overexpression	No change	Increased drought tolerance due to reduced stomatal conductance	Fotopoulos et al. 2008
	Tobacco	AAO	Pumpkin	Overexpression	2.0-fold increase in apoplastic ASA	Number of smaller flowers significantly increased 6% to 14% reduction of in seed weight	Pignocchi et al. 2003
			Tobacco	Antisense downregulation	2.0-fold increase in apoplastic ASA	No significant changes
	Tobacco	AAO	Tobacco	Overexpression	–	Severe inhibition of germination and seed yield under high salinity	Yamamoto et al. 2005
	Tobacco	AAO	Tobacco	Antisense downregulation	–	Increased tolerance to salt stress	Yamamoto et al. 2005
					–	Increased seed yield under salt stress
	Arabidopsis	AAO	–	T-DNA knockout		Increased tolerance to salt stress
						Increased seed yield under salt stress
Myoinositol oxygenase	Rice	OsMIOX	Rice	Overexpression	No change	Increased drought tolerance	Duan et al. 2012a
ASA mannose pathway regulator 1	Arabidopsis	AMR1	–	T-DNA knockout	2.0–3.0-fold increase	Increased ozone tolerance	Zhang et al. 2009

APx-R, APX-related; CAPOA1, Capsicum annuum ascorbate peroxidase-like 1 gene; MV, methyl viologen; NPR, net photosynthetic rate; PEG, polyethylene glycol; RNAi, RNA interference; VIGS, Virus-induced gene silencing; VVMEE, Viral-vector-mediated ectopic- expression.