Abstract:ACC （1-aminocyclopropane-l-carboxylic acid） synthase （ACS）is one of the key rate-limiting enzymes for ethylene biosynthesis in higher plants. In this paper, two degenerate oligonucleotide primers were designed, coding for conservative amino acid regions in ACC synthase protein family. PCR amplification was performed on sugarcane DNA template, and produced three fragments, 1 041 bp （Sc-ACS1）, 1 345 bp （Sc-A CS2） and 1 707 bp （Sc-A CS3）. By using the program of BLAST on NCBI GenBank database, three sequences were all ACC synthase genes, coded 326, 242 and 310 amino acids, respectively. The identity of Sc-A CS1 and Sc-A CS3 was 98% in DNA sequence and 96% at amino acid level, and that ofA CS genes from other grass plant species Zea mays （Zm A CS6）, Oryza stativa （OS-A CS2） and Phyllostaehys edulis （BA-A CS） reached to 88%-98% in DNA sequence and 73%-81% in amino acid sequence. The identity of Sc-A CS2, compared to OS-A CS5 from Oryza stativa, was 91% in DNA sequence and 79% at amino acid level, which was higher than that for Sc-A CS1 （45%） and Sc-A CS3 （49%） from sugarcane. Phylogenetic analysis showed that the genes of Sc-ACS1 and Sc-ACS3 in sugarcane were closely related to Zm A CS6 in maize, while Sc-A CS2 was closely related to OS-A CS5 in rice. Southern blotting analysis showed that these genes were presented in the genomic DNA with multiple copies. The three sequences have been registered in GenBank with the accession numbers AY620985, AY620986 and AY788919.
