Table 2.

Transgenic approaches manipulating genes controlling amino acid metabolism and transport to improve nitrogen use efficiency in rice

Gene	Source	Promoter used	Phenotype observed	Reference
PTR6	Oryza sativa L.	Ubiquitin	Increased plant growth	30
AMT1.1	Oryza sativa L.	Ubiquitin	Increased ammonium, uptake and seed yield	121
AMT2.1	Oryza sativa L.	CaMV 35S	Increased Ammonium uptake	98
GS1	Oryza sativa L.	CaMV 35S	Increased N, decreased seed yield	107
GS2	Oryza sativa L.	CaMV 35S	Photorespiration capacity up	46
GOGAT	Oryza sativa L.	CaMV 35S	Increased grain weight	47
AlaAT	Hordeum vulgare L.	OsAnt1	Increased biomass and seed yield	122
GDHA	Aspergillus	CaMV 35S	Increased DW, N, yield in field	51
DOF1	Zea mays L.	CaMV 35S	Increase nitrogen content 30%, enhance growth rate under low N, reduced glucose level	123
ENOD93–1	Oryza sativa L.	Ubiquitin	Increased shoot biomass and seed yield	49
glnA	Escherichia col	CaMV 35S	Increase grain yield under high, moderate and low N conditions	124
GS1.1, GS2	Oryza sativa L.	CaMV 35S	Increase N assimilation and plant biomass	125
OsGOGAT1	Oryza sativa L.	Activation tagging lines	Increase NUpE in low N conditions; increase N content of grains	126
ASN1	Oryza sativa L.	Ubiquitin	Increase N content of grains; no impact on grain yield	127
gdhA	Aspergillus niger	CaMV 35S	Increase ammonia assimilation and plant biomass under high N conditions	51
GDH	Trichurus	Ubiquitin	Increase N assimilation, thousand grain weight, grain number and seed protein content under high, moderate and low N field conditions	128
SHMT1	Oryza sativa L.	Actin	Increased photosynthesis and grain number per panicle	53
ALAAT	Hordeum vulgare L.	Ant1	Increase plant biomass, NUpE and final seed yield under high N conditions independently of soil N source [ammonia/nitrate]	122
ALAAT2	Cucumis sativa L.	Ant1	Increase NUpE and grain yield in high and moderate N conditions	129
AAP1	Oryza sativa L.	CaMV 35S	Increase tiller number and grain yield	54
AAP3	Oryza sativa L.	CaMV 35S	Decrease tiller number and grain yield	55
AAP5	Oryza sativa L.	CaMV 35S	Decrease tiller number and grain yield	130
AAP6	Oryza sativa L.	CaMV 35S	Increase amino acid uptake from roots, amino acid transport and grain protein content at final harvest; maintain grain yield	57