Table A1.

Primers sequences used in performing the real-time PCR.

Primer Name	Forward primer sequence	Reverse primer sequence	Accession number
ZmTub2	5′GCGCCTGTCTGTTGACTATGG3′	5′GGGATGGGTACACGGTGAAA3′	gi|195610153
ZmNRT1.1	5′CTGTCTGGCACCGTGATTGT3′	5′CGTAGCTGACTGCCCACCTAA3′	gi|37778585
ZmNRT1.2	5′TGTTCTCGGCGTGGTGAA3′	5′CCTCTGTACCTGACGGAGCAA3′	gi|63397127
ZmNRT2.2	5′CTCAGGTCGCTGCAGAAGAAG3′	5′CGTACCACATGACCTTGGAGAA3′	gi|49472846
ZmNRT2.3	5′CTTCTTCACCACGTCCAGCTACT3′	5′GCCATGATGCCCATGTTCTC3′	gi|63397156
ZmGln1	5′GACGGCGGGTTTGAAGAGA3′	5′TCATGGCGCAGAGAAAGGTT3′	gi|162459402
ZmGln2	5′GACGGCGGGTTTGAAGAGA3′	5′TCATGGCGCAGAGAAAGGTT3′	gi|434333
ZmGln4	5′AGGGCAGTGGGAGTTCCAA3′	5′AGACCTGGTCGCCTGAAGATATAC3′	gi|162463754
ZmGln5	5′CCGTCCGTCGGCATCTC3′	5′CCTCTCAAGAATGTAGCGAGCAA3′	gi|162459550
ZmGs1.3	5′AGGGCAGTGGGAGTTCCAA3′	5′ACCTGGTCGCCTGAAGAAATAC3′	gi|434327
ZmGs1.4	5′GCCAATTCCCACCAACAAGA3′	5′GACCTCAGGGCTGCTGAAGA3′	gi|434329
ZmNR1	5′CGAGATCGGCCACTTCGA3′	5′AACTTAGGGTGCTCGTTCTTGAA3′	gi|168518
ZmNR2	5′GAGTGGACGAGCATGTCATGA3′	5′CGCAATGGTCTCGCTGTCT3′	gi|22376
ZmNAR1S	5′CAAGGTGTGGTACGTCATCGA3′	5′GAACCCAACGCTGTACTTCCA3′	gi|168516
ZmNiR	5′CCTGCCGAGGAAATGGAA3′	5′TACGCGAGGTCGTTGATGTG3′	gi|623203
ZmF-NiR	5′CCTGCCGAGGAAATGGAA3′	5′TACGCGAGGTCGTTGATGTG3′	gi|195615807
ZmAGPP	5′CCAGGGTTGGAAGGAACGT3′	5′CGGTCGGGACTCTTGGAA3′	gi|558364
ZmSuPP	5′GAACATGGCGACACCGATCT3′	5′CGGACGATCACGGTCTTGT3′	gi|162460833
ZmSS	5′CGGACGGCTACACCAACTACTC3′	5′TTGCACTGCCGCTTTCC3′	gi|45825439