Table 1.

Increase the levels of essential amino acids lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) in transgenic horticultural plants.

Amino Acid	Plant	Transgene	Tissue	Free fold Increase T/WT (Souble)	Phenotype	References
Lys	Potato	Constitutive::DHDPS	Leaves	2–4	ND	[20]
	Potato	Constitutive::DHDPS	Roots	1.2–5	ND	[20]
	Potato	Constitutive::DHDPS	Tubers	2–3.5	ND	[20]
	Tobacco	Constitutive::AK	Leaves	1.1–2	ND	[39]
	Tobacco	Constitutive::DHDPS	Leaves	9–11	A partial loss of apical dominance, delayed flowering and senescence, partial sterility, and abnormal leaf morphology	[15]
	Tobacco	Seed-specific::DHDPS	Seeds	1–2	ND	[23]
	Canola	Seed-specific::DHDPS/AK	Seeds	More than 100	ND	[21]
	Soybean	Seed-specific::DHDPS/AK	Seeds	Several hundreds	Wrinkled seed with poor germinaiton	[21]
	Soybean	Soybean vegetative storage proteins(S-VSPs)	Leaves	NR	ND	[40]
	Tobacco	Constitutive::DHDPS	Leaves	30	Mosaic green color in newly developed leaves at the tip of the apex and partial loss of apical dominance	[22]
	Tobacco	Constitutive::DHDPS/Constitutive::AtCGS	Leaves	24	ND	[22]
Thr	Tobacco	Constitutive::AK	Leaves	2–8	ND	[39]
	Tobacco	Constitutive::DHDPS	Leaves	6–8	A partial loss of apical dominance, delayed flowering and senescence, partial sterility,and abnormal leaf morphology	[15]
	Tobacco	Seed-specific::DHDPS	Seeds	1	ND	[23]
	Tobacco	Supress AK	Seeds	About 5.8	ND	[23]
	Tobacco	Seed-specific::DHDPS/AK	Seeds	About 3.9	ND	[23]
	Tobacco	Constitutive::AtCGS	Leaves	1.8	ND	[22]
	Tobacco	Constitutive::CGS/AK	Leaves	173	ND	[30]
Met	Tobacco	antisense SAMS	Leaves	433	Vein showed dark gren	[41]
	Vicia narbonensis	Seed-specific::2S BN/AK	Seeds	2	ND	[42]
	Lupin	Seed-specific::2S SSA	Seeds	2	Statistically significant increases in live weight gain, true protein digestibility, biological value, and net protein utilization	[26]
	Potato	Antisense TS	Leaves	239	Severe growth retardation, strong chlorosis, and an acute reduction in tuber yield	[31]
	Potato	Constitutive::AtCGS	Leaves	2–7.1	ND	[43]
	Potato	Constitutive::AtCGS	Root	1.2–4.1	ND	[43]
	Bean	Seed-specific::2S BN	Seeds	1.25	ND	[44]
	Chickpea	Seed-specific::2S SSA	Seeds	1.9	ND	[45]
	Alfalfa	Constitutive::AtCGS	Leaves	37	ND	[46]
	Tobacco	Constitutive::DHDPS	Leaves	2	ND	[22]
	Tobacco	Constitutive::AtCGS	Leaves	5	ND	[22]
	Tobacco	Constitutive::DHDPS/Constitutive::AtCGS	Leaves	10	ND	[22]
	Tobacco	Constitutive::CGS/AK	Leaves	39		[22]
	Potato	Constitutive::AtCGS/zein	Tubers	2–6	ND	[47]
	Tobacco	Constitutive::CGS/AK	Leaves	39	ND	[30]
	Soybean	Seed -specific::AtCGS	Seeds	2.1	ND	[48]
	Azuki bean	Seed -specific::AtCGS	Seeds	2.3	ND	[48]
Trp	Astragalus	Constitutive::ASA2	Hariy roots	1.3–5.5	ND	[49]
	Tobacoo	Constitutive::ASA2	Leaves	16	ND	[50]
	Tobacco	Constitutive::CGS/AK	Leaves	39	ND	[30]
	Soybean	Seed -specific::OASA1D	Seeds	50.9	ND	[51]

Abbreviations: DHDPS, feedback-insensitive dihydrodipicolinate synthase; AK, feedback-insensitive Asp kinase; AtCGS, Arabidopsis thaliana cystathionine γ-synthase; TS, Thr synthase; 2S SSA, 2S sunflower seed albumin; 2S BN, 2S brazil nut albumin; OASA1D, rice mutated feedback-resistant a subunit of rice anthranilate synthase; NtASA2, tobacco feedback-insensitive anthranilate synthase 2; ND, not detected.