1. ATGGCAAAAGATCGTCGCAGTAATGAAGCTGAAAATATCGCTGTTGTTGAAAAACCGCTGAAATCGGACCG CTTCTTTA TCTCTGATGGTCTGCCGAGTCCGTTCGGCCCGACCGTTCGTGATGACGGTGTGAATTTTTCTGTTTATAGT ACCAACTCT GTCAGTGCGACGATTTGCCTGATCTCCCTGTCAGACCTGCGCCAGAATAAAGTGACCGAAGAAATTCAAC TGGACCCGAG CCGTAACCGCACGGGCCATGTGTGGCACGTTTTTCTGCGTGGTGACTTCAAAGATATGCTGTACGGTTAT CGCTTTGATG GCAAATTCAGTCCGGAAGAAGGCCATTATTACGACAGCTCTAATATCCTGCTGGACCCGTATGCAAAAGCT ATTATCTCC CGTGATGAATTCGGCGTGCTGGGTCCGGATGACAACTGCTGGCCGCAGATGGCGTGTATGGTTCCGACC CGTGAAGAAGA ATTTGACTGGGAAGGTGATATGCACCTGAAACTGCCGCAAAAAGACCTGGTTATTTACGAAATGCATGTCC GTGGCTTTA CCCGCCACGAAAGTTCCAAAATCGAATTCCCGGGCACGTATCAGGGCGTGGCCGAAAAACTGGATCATCT GAAAGAACTG GGTATTAATTGCATCGAACTGATGCCGTGTCACGAATTCAACGAACTGGAATACTACAGTTACAACACCAT TCTGGGCGA TCATCGTGTTAACTTTTGGGGTTACTCGACGATTGGCTTTTTCAGCCCGATGATCCGTTATGCGTCTGCCT CATCGAACA ATTTTGCAGGCCGCGCTATCAACGAATTCAAAATCCTGGTTAAAGAAGCGCATAAACGTGGTATTGAAGTC ATCATGGAT GTGGTTCTGAATCACACCGCCGAGGGTAACGAAAAAGGCCCGATCTTTTCTTTCCGCGGCGTCGATAACA GTGTGTATTA CATGCTGGCGCCGAAGGGTGAATTTTACAATTATAGCGGCTGCGGTAACACCTTCAATTGTAACCATCCG GTCGTGCGTC AGTTTATTCTGGATTGCCTGCGCTACTGGGTGACGGAAATGCACGTTGACGGTTTTCGTTTCGATCTGGGC TCCATCATG TCACGCAGCTCTAGTCTGTGGGATGCGGCCAATGTCTATGGTGCGGACGTGGAAGGCGATCTGCTGACC ACGGGTACCCC GATTAGTTGTCCGCCGGTCATTGACATGATCTCCAACGATCCGATTCTGCGTGGCGTGAAACTGATCGCA GAAGCGTGGG ATGCCGGCGGTCTGTACCAAGTGGGCATGTTTCCGCATTGGGGCATTTGGAGCGAATGGAATGGTAAATT TCGTGACGTT GTCCGCCAATTCATCAAAGGCACCGATGGTTTTTCAGGCGCGTTCGCCGAATGCCTGTGTGGTTCGCCGA ATCTGTATCA GGGCGGTCGCAAACCGTGGCATAGCATTAACTTTATCTGCGCACACGACGGCTTCACCCTGGCTGATCTG GTGACGTACA ACAATAAAAACAATCTGGCAAATGGTGAAGAAAACAATGACGGCGAAAATCACAACTATAGCTGGAACTGT GGTGAAGAA GGCGATTTTGCTTCGATTAGCGTTAAACGTCTGCGCAAACGTCAGATGCGTAACTTTTTCGTTAGCCTGAT GGTCTCTCA AGGCGTGCCGATGATCTACATGGGTGACGAATATGGCCATACCAAAGGCGGTAACAATAACACGTACTGC CACGATAACT ACATGAACTACTTCCGCTGGGACAAAAAAGAAGAAGCGCATAGTGATTTCTTTCGCTTTTGCCGTATTCTG ATCAAATTC CGTGACGAATGTGAATCCCTGGGCCTGAATGATTTTCCGACCGCGAAACGTCTGCAGTGGCATGGTCTGG CACCGGAAAT TCCGAACTGGTCGGAAACGAGCCGTTTTGTGGCCTTCAGTCTGGTCGATTCCGTGAAAAAAGAAATCTAC GTGGCGTTCA ATACCTCCCATCTGGCCACGCTGGTTTCACTGCCGAACCGTCCGGGTTACCGTTGGGAACCGTTTGTGGA TACCTCTAAA CCGAGTCCGTATGACTGTATTACCCCGGATCTGCCGGAACGTGAAACGGCAATGAAACAGTATCGCCACT TTCTGGATGC TAATGTTTACCCGATGCTGTCATATTCCTCAATTATCCTGCTGCTGTCGCCGATTAAAGATCCGA AtISA1

2. ATGGCACGTCTGTTTACCGGCCGCAAAAACAAAATCAAACTGGGTTCGGAAACCCTGATGTTTACGCGC AAACGTTTCA TGGGTGATCTGGTGACCTCAGCGCTGCAGTCGTACCAATTTAGCAAAATTTGCGCGTCCAAAACGTCAA TCGAACTGCGT GAAGCCCTGTCGAGCCGTCGCGCAGAAGCTGATGACCTGAAAAAAGTTACCTCTTACAGTTTCCGTACG AAAGCGGGCGC CCTGGTCAAAGTGAAAGTTGAGAAAAAACGTGAAAAATACAGCATTCTGGTCTATGTGTCTAGTCTGGAA CTGTCCGGCG ATGACAAATCACGTCTGGTTATGGTCTGGGGTGTGTACCGCTCTGATTCCTCATGTTTTCTGCCGCTGGA CTTCGAAAAT TCGAGCCAGGATAGTCAAACCCATACCACGGAAACCACGTTCGTTAAATCTAGTCTGTCCGAACTGATG CTGGGTCTGGA ATTTGATGGCAAAGAATCGCCGTTTTATCTGAGCTTCCACCTGAAACTGGTTAGCGGTCGTGACCCGGAT GGCCAGGAAA TGCTGACCCATCGCGACACGGATTTTTGCATTCCGGTTGGTTTTACCGCCGGTCACCCGCTGCCGCTGG GTCTGTCCTCA GGCCCGGATGACGATTCCTGGAATTTTTCGTTTTTCAGCCGTTCGAGCACGAACGTGGTTCTGTGTCTGT ACGACGATTC AACCACGGACAAACCGGCGCTGGAACTGGATCTGGACCCGTATGTGAATCGCACCGGCGATGTTTGGC ATGCCTCAGTCG ACAACACGTGGGATTTTGTTCGTTACGGTTATCGCTGCAAAGAAACCGCACACTCGAAAGAAGACGTGG ATGTTGAAGGC GAACCGATTGTTCTGGACCCGTACGCTACGGTCGTGGGCAAATCCGTCTCACAGAAATATCTGGGTTCG CTGAGCAAATC TCCGAGTTTTGACTGGGGTGAAGATGTGAGCCCGAATATCCCGCTGGAAAAACTGCTGGTGTATCGTCT GAACGTTAAAG GCTTCACCCAACATCGCTCTAGTAAACTGCCGTCGAATGTGGCAGGCACGTTTAGCGGCGTTGCTGAAA AAGTCTCTCAC CTGAAAACCCTGGGTACGAACGCCGTTCTGCTGGAACCGATTTTTAGCTTCTCAGAACAGAAAGGCCCG TACTTTCCGTT CCATTTCTTTAGCCCGATGGATATCTATGGTCCGTCGAATAGCCTGGAATCTGCAGTCAACAGTATGAAA GTCATGGTGA AAAAACTGCATAGCGAAGGTATTGAAGTTCTGCTGGAAGTTGTCTTTACCCACACGGCAGATTCTGGTGC TCTGCGTGGC ATCGACGATTCCTCATATTACTATAAAGGCCGCGCAAATGACCTGGATTCTAAAAGTTACCTGAATTGCA ACTATCCGGT GGTTCAGCAACTGGTGCTGGAAAGCCTGCGTTATTGGGTCACCGAATTCCATGTGGATGGCTTTTGTTT CATTAATGCGA GCAGCCTGCTGCGTGGTGTTCATGGTGAACAGCTGTCTCGCCCGCCGCTGGTTGAAGCAATTGCTTTTG ATCCGCTGCTG GCCGAAACCAAACTGATCGCCGACTGTTGGGACCCGCTGGAAATGATGCCGAAAGAAGTGCGTTTCCC GCATTGGAAACG CTGGGCGGAACTGAACACCCGCTACTGCCGTAATGTCCGCAACTTTCTGCGTGGTCGTGGTGTGCTGA GCGATCTGGCAA CCCGCATTTGTGGCTCTGGTGACGTTTTCACGGATGGCCGTGGTCCGGCTTTTAGCTTCAATTATATTTC TCGCAACAGT GGCCTGTCCCTGGTTGATATCGTCTCCTTTTCAGGTCCGGAACTGGCCTCAGAACTGTCGTGGAATTGC GGTGAAGAAGG CGCGACCAACAAATCTGCCGTGCTGCAGCGTCGCCTGAAACAAATCCGTAATTTTCTGTTCATCCAGTAC ATCAGTCTGG GCGTTCCGGTCCTGAACATGGGTGACGAATGTGGCATCTCCACCCGTGGTTCACCGCTGCTGGAAAGC CGCAAACCGTTT GATTGGAATCTGCTGGCGTCTGCCTTCGGCACCCAGATTACGCAATTTATCTCGTTCATGACCAGCGTG CGTGCCCGTCG CAGCGACGTTTTTCAGCGTCGCGATTTCCTGAAACCGGAAAATATTGTGTGGTATGCCAACGACCAAAC CACGCCGAAAT GGGAAGATCCGGCATCTAAATTTCTGGCTCTGGAAATCAAATCGGAAAGCGAAGAAGAAGAAACCGCGA GTCTGGCCGAA CCGAATGAACCGAAATCCAACGACCTGTTTATTGGTTTCAACGCGTCTGATCATCCGGAAAGTGTCGTGC TGCCGTCCCT GCCGGATGGCTCAAAATGGCGTCGCCTGGTGGATACCGCACTGCCGTTTCCGGGCTTTTTCAGCGTTG AAGGCGAAACGG TTGTCGCTGAAGAACCGCTGCAGCAACTGGTGGTTTATGAAATGAAACCGTACTCTTGCACCCTGTTCGA AACCATCAAT ACCACCGCCC AtISA2 ATGGCTGAAGCAGTCCAAGCAGAAGAAGACGATGATGATGATGATGAAGAAGTGGCTGAAGAACGTTTT GCCCTGGGTG GTGCGTGCCGTGTGCTGGCGGGTATGCCGGCACCGCTGGGTGCAACCGCACTGCGCGGCGGTGTCAA CTTCGCTGTGTAT AGCTCTGGTGCGTCCGCGGCCTCACTGTGTCTGTTTGCCCCGGGCGACCTGAAAGCAGATCGTGTTAC CGAAGAAGTCCC GCTGGACCCGCTGCTGAATCGTACCGGTAACGTTTGGCATGTCTTTATTCACGGCGACCAGCTGCACG GTATGCTGTATG GCTACCGCTTTGATGGTGTGTTCGCCCCGGAACGTGGCCAATATTACGACGTTAGCAATGTGGTTGTCG ATCCGTATGCT AAAGCGGTGGTTTCGCGCGGTGAATATGGTGTTCCGGCTCCGGGCGGTAGCTGCTGGCCGCAGATGG CGGGTATGATCCC GCTGCCGTACAACAAATTCGACTGGCAGGGTGATCTGCCGCTGGGCTATCATCAAAAAGACCTGGTGAT TTACGAAATGC ATCTGCGTGGTTTTACCAAACACAATAGTTCCAAAACCAAACATCCGGGCACGTATATTGGCGCGGTCA GCAAACTGGAT CACCTGAAAGAACTGGGCGTGAATTGCATCGAACTGATGCCGTGTCATGAATTCAACGAACTGGAATAC TTCTCATCGAG CTCTAAAATGAACTTTTGGGGTTACTCGACCATTAACTTTTTCAGCCCGATGGCACGCTATAGTTCCTCA GGCATTCGTG ATAGCGGTTGTGGCGCGATCAACGAATTTAAAGCCTTCGTCCGCGAAGCACACAAACGTGGCATTGAAG TGATCATGGAT GTCGTGTTCAATCATACGGCCGAGGGTAACGAAAAAGGCCCGATTCTGTCGTTTCGCGGTATCGATAAT AGCACCTATTA CATGCTGGCACCGAAAGGCGAATTTTATAATTACTCTGGTTGCGGCAACACGTTCAATTGTAACCACCCG GTTGTCCGCG AATTTATTGTGGATTGCCTGCGTTACTGGGTGACCGAAATGCATGTTGATGGTTTTCGCTTCGACCTGGC GTCTATCCTG ACGCGTGGCTGTAGTCTGTGGGACCCGGTTAACGTCTATGGTTCGCCGATGGAAGGCGATATGATTAC CACCGGTACCCC GCTGGTTGCGCCGCCGCTGATTGATATGATCAGTAATGACCCGATTCTGGGCAACGTGAAACTGATCGC CGAAGCATGGG ATGCCGGCGGTCTGTACCAGGTTGGTCAATTCCCGCATTGGAATGTCTGGAGCGAATGGAACGGCAAA TATCGCGACACC GTGCGTCAGTTTATCAAGGGTACGGATGGCTTTGCTGGTGCGTTCGCCGAATGCCTGTGTGGTTCGCC GCAGCTGTATCA AGCAGGCGGTCGTAAACCGTGGCACAGCATTAATTTTGTTTGCGCCCATGACGGCTTCACCCTGGCGG ATCTGGTGACGT ATAATTCGAAATACAATCTGAGCAACGGTGAAGACAACCGCGATGGCGAAAATCACAACCTGTCTTGGA ATTGCGGCGAA GAAGGTGAATTTGCCTCTCTGAGTGTGCGTCGCCTGCGTAAACGCCAGATGCGTAACTTTTTCGTGTGT CTGATGGTTAG CCAAGGTGTCCCGATGTTCTATATGGGTGACGAATACGGCCATACCAAAGGCGGTAACAATAACACGTA CTGTCATGATC ACTATGTGAATTACTTTCGCTGGGACAAAAAAGAAGAACAGTCGAGCGATCTGTATCGCTTTTGCCGTCT GATGACCAAA TTCCGCAAAGAATGTGAATCGCTGGGTCTGGAAGATTTTCCGACGAGCGAACGTCTGAAATGGCATGGC CACCAACCGGA AAAACCGGACTGGTCGGAAGCTAGCCGTTTTGTTGCGTTCACCATGAAAGATGAAACGAAAGGCGAAAT TTATGTGGCGT TTAACACCTCTCACCTGCCGGTGGTTGTCGGTCTGCCGGAACGCAGTGGCTTCCGTTGGGAACCGGTG GTTGATACGGGT AAAGAAGCACCGTACGACTTTCTGACCGATGGTCTGCCGGACCGTGCTGTGACCGTTTACCAGTTCTCT CATTTCCTGAA CAGTAACCTGTATCCGATGCTGAGCTACTCTAGTATTATCCTGGTCCTGCGTCCGGATGTGA ZmISA1

3. ATGGCAGCTGCGCGCAGTTATCGTTACCGCTTTCGTACCGATGACGATGGCGTCGTGGATGTCGCAGTGGC TGGCAAAG ACGGTGATGCGGGCTATGTTGTCGCAATTGAAGCTCCGACCCACGGTCAGCGCGGCGGTCTGGTTCTGCGC CCGGCAGGT TCTGGTGAAGGTGTTCCGCTGGCACCGGCGGCACCGGGCGGTGCGCTGGTCGCCGAACTGTCCTATGACG TGGCGCGTGC CCCGTTTCACGTTTCATTCACCCTGGCAGATGCTATGGGTGCGGAAATTCGCACCCATCGTGGCACGTCCTT TCGTGTTC CGGTTGGTGTGGGTCGTGGTTGTCCGTCACCGCTGGGTCTGTCCCAGTCAAAAGATGGCGCTGCGAATTTC GCTGTGTAC AGCAAAATTGCGAAGGGTATGGTTCTGTGTCTGTTTGGCGGTGGCGGTGGCGATGGTCCGGCACTGGAAAT CGAACTGGA CCCGTATGTTCACCGCACCGGTGATGTGTGGCATGTTTCTATGGAAAGTGTGGAAGGCTATGCCCGCTACG GTTTCCGTT CCGGCCTGTTTGCAATGTTCGGCATTGATCGTCCGCTGCTGGACCCGTATGCTAAAGTTATCGGTGATTTTG TCGCGGGC GACAGCGTGGACGAAGATGGTCTGGCGGTGCCGTCCATTCGTTGCCTGGCCTCACTGAAAAATGCACCGAA CTACGATTG GGGCCGCGACAAACATCCGTGTCTGCCGCTGCAGAAACTGGTGGTTTATCGTGCAAACGTTGCTCTGTTTAC CAAAGACC GCTCCTCACGTCTGGCTGATAATGCCGCAGGCACGTTCTCCGGCATGTCAGCGAAAGTGGAACATTTTCGC CACCTGGGT GTCAACGCCGTGCTGCTGGAACCGGTGTTTCCGTTCCACCAAGTTAAAGGCCCGTATTTTCCGTACCATTTC TTTAGCCC GATGAGCCTGTATTCGAGCGAATGCTCTAGTGTGTCCGCGATCAAATCAATGAAAGATATGGTTAAAACCATG CACCGCA ATGGTATCGAAGTCCTGCTGGAAGTCGTGTTTACCCATACGGCAGAAGGTGGCGCTGAATGTCAGATGATTA GCCTGCGT GGTATCGACGGCTCCTCATATTACATTGCGGATGGTATCGCCGGCTGCAAAGCATCGGTCCTGAATTGTAAC CACCCGGT GACCCAAAAACTGATTCTGGATAGCCTGCGCCATTGGGTTCTGGATTTCCACGTCGACGGCTTTTGCTTCATT AATGCAC CGTTTCTGGTGCGTGGTCCGGGTGGCGAAGGTCTGTCTCGTCCGCCGCTGCTGGAAGCCATTGCCTTTGAT CCGGTTCTG AGTAAAACCAAAATTATCGCAGACCCGTGGTCCCCGCTGGATATCTCAAACGTGCAGTTTCCGTTCCCGCAT TGGAAACG TTGGGCGGAAATGAATACCCGCTTTTCTATGGATGTTCGTAAATTCCTGAAAGGTGAAGCCCTGATTTCTGAC CTGGCAA CGCGCCTGTGTGGTAGTGGCGACCTGTTTAGCAGCCGTGGCCCGGCCTTTTCTTTCAATTACGTGTCTCGCA ACAGTGGC CTGACCCTGGTTGACCTGGTCAGTTTTTCTAGTGATGAACTGGCCTCCGAATTCTCATGGAACTATGGTGAA GAAGGCCC GAGTGAAAATAACGCAGTTTTCCAGACCCGCCTGCGTCAAATCCATAATTTTCTGTTCATCCTGTTCATCTCC CTGGGCA TCCCGGTGCTGAATATGGGTGACGAATGCGGCAACTCAGCTGCGGGTTCGACCAGCTATAAAGATCGTGGC CTGCTGAAC TGGAAAGCTCTGAAAACCGCGTTTGTGAAAGAAGTTACGGGTTTTATCTCGTTCCTGAGCGCTCTGCGCAGC CGTCGCGC CGATATTTTTCAGCGTTGTGAATTCCTGAAACTGGAAAATATCCACTGGTACGGCTCTGACCTGAGTGAACCG TGCTGGG AAGATCCGACCTCCAATTTCCTGTGTCTGCATATTAACGCGGAACTGGATGAAAAACTGCCGGACTCAACGG GTGGCGAT CTGTATATTTGCTTTAATGCCAACGAAGAATCTGCAAGTGCTACCCTGCCGGCGATCGCCGAAGGTAGCATG TGGCTGCG TCTGGTTGATACGTCCCTGGCGTTCCCGGGCTTTTTCAGCCGTGGCAGCAGCCATGAAACCCACCAGGTGC TGGGCTTTT CGAGCTATCAAGTCAAAGCCCATAGCTGCGTCCTGTTCGAAAGCAAACGTGTCCTGAGCC ZmISA2 Supplemental Figure S1: Top panel : this picture exemplifies the construction of the vectors designed for expression in E. coli. ISA1 and ISA2 genes (from maize or Arabidopsis) optimized for expression in E. coli (see below) were synthesized in the form of an operon including START and STOP codons for each ORF and integrated in vector pUC57. From this vector, several constructions were made by transferring ISA1 or ISA2 or ISA1 and ISA2 into the destination vector pBE1343. ISA1 was transferred after digestion with BglII and HindIII and ISA2 was transferred after the digestion with BamH1 and XhoI. In both cases, the corresponding proteins were tagged with the 8xHis sequence (the STOP codon being placed downstream of the tag). The transfer of both ISA1 and ISA2 as a operon into pBE1343 was achieved by the digestion with both BglII and XhoI. In that case, only ISA2 was tagged with the 8xHis sequence. Sequences of maize (Zm) and Arabidopsis (At) ISA1 and ISA2 structural genes optimized for expression in E. coli are shown from the start codon to the last codon that specifies the protein. The stop codon is not shown here, as it is included in the expression vector.