Genomic characterization of the S-adenosylmethionine decarboxylase genes from soybean.
A full-length gene GmSAMDC1, encoding the S-adenosylmethionine decarboxylase (SAMDC), a key enzyme involved in polyamine biosynthesis, was identified from soybean expressed sequence tags and was characterized. GmSAMDC1 encoded a peptide of 355 amino acids. When compared with other plant SAMDCs, the GmSAMDC1 protein had several highly conserved regions including a putative pro-enzyme cleavage site and a PEST sequence. The 5' leader sequence of the the GmSAMDC1 mRNA contained two additional open reading frames (ORFs), which may regulate the translational process. The genomic sequence of the GmSAMDC1 gene contained three introns in the 5' leader sequence, but no intron in the 3'-UTR or the main pro-enzyme ORF. A simple sequence repeat (SSR) was found in intron 2, and the GmSAMDC1 gene was mapped to linkage group D1 using this SSR. The genomic organization of the GmSAMDC1 gene in the subgenus Glycine and the subgenus Soja was found to be different by Southern-blot and PCR analysis. A pseudogene, GmSAMDC2, was also identified. This gene contained no intron and lost its two uORFs. Northern-blot analysis showed that the GmSAMDC1 gene expression was induced by salt, drought and cold, but not induced by wounding; suggesting that the gene was implicated in response to multiple-stress conditions.
Tian
Ai-Guo
AG
Plant Biotechnology Laboratory, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 100101, Beijing, China.
Zhao
Jing-Yun
JY
Zhang
Jin-Song
JS
Gai
Jun-Yi
JY
Chen
Shou-Yi
SY
D020413:3' Untranslated Regions; D012437:Adenosylmethionine Decarboxylase / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D017931:DNA Primers; D018076:DNA, Complementary; D017343:Genes, Plant; D018745:Genome, Plant; D007438:Introns; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D011544:Pseudogenes; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013025:Glycine max / Q000235:genetics*
D020413:3' Untranslated Regions; D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D012437:Adenosylmethionine Decarboxylase