Validation of Candidate Genes

Leaf amino acid profile changes in response to N among B73 x IHP1, B73 x ILP1, and B73 x Mo17 hybrids. The transport and storage amino acid asparagine (Asn) increases relative to metabolically active glutamine (Gln) in response to N and the IHP genotype.

The metabolic pahtway for asparagine accumulation.

B73 and IHP1 plants were grown in hydroponics under either Ndeficient (1 mM NO3 -) or Nsufficient (14 mM NO3 -) conditions. Leaves were sampled from these plants during both the day and night. RNA was isolated and the relative expression of genes encoding an asparagine synthetase (AS2) or asparaginase isoform was assayed by qRT-PCR.

Quantitative Real-Time PCR analysis of NitroGenes:
AS2 RNA expression increases in response to N and is also elevated in IHP1 relative to B73, particularly during the day. Conversely, asparaginase RNA expression is repressed by N, and is greatly reduced in IHP1 compared to B73.