Biotic and abiotic stress-related expression of 1-aminocyclopropane-1-carboxylate oxidase gene family in Nicotiana glutinosa L.
Three full length 1-aminocyclopropane-1-carboxylate (ACC) oxidase cDNA clones (pNG-ACO1, 1,254 bp; pNG-ACO2, 1,198 bp; and pNG-ACO3, 1,053 bp) were isolated from the TMV-treated leaf cDNA library of Nicotiana glutinosa plant. They share a high degree of sequence identity (78-81%) throughout the coding regions but are divergent within the 3'-untranslated regions. The gene-specific probes were prepared using these regions to investigate the differential expression of the ACC oxidase gene family in various organs and in response to a multitude of biotic and abiotic stresses in N. glutinosa plants. All three genes were transcriptionally active displaying unique patterns of expression. Both the pNG-ACO1 and pNG-ACO3 transcripts highly accumulated during the senescence of leaves, while the pNG-ACO2 mRNA was constitutively present. In addition, the NG-ACO1 and NG-ACO3 transcripts were predominantly found in roots whereas the NG-ACO2 mRNA was mainly in stems. Upon TMV infection, both NG-ACO1 and NG-ACO3 were markedly induced, but in mock treatment which has an effect of mild wounding, only the NG-ACO3 gene was induced. Furthermore, salicylic acid and CuSO4 treatments of leaves increased the level of NG-ACO1 and NG-ACO3 transcripts, while they did not affect the NG-ACO2 gene expression. Results showed that both the NG-ACO1 and NG-ACO3 genes were highly inducible by ethylene and methyl jasmonate treatments, with NG-ACO3 being more responsive. By contrast, NG-ACO2 did not respond to these growth regulators. Thus, it appears that there are two groups of ACC oxidase transcripts expressed in leaf tissue of N. glutinosa, either stress-induced or constitutive. The possible molecular mechanism of differential regulation of ACC oxidase gene expression and its physiological significance are discussed.
Department of Biology, College of Science, Yonsei University, Seoul, Korea.
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Kim
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Choi
M M
MM
Lee
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Lee
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Kim
D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D014644:Genetic Variation; D008969:Molecular Sequence Data; D005810:Multigene Family; D018515:Plant Leaves; D018517:Plant Roots; D010947:Plants, Toxic; D012333:RNA, Messenger / Q000096:biosynthesis; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic
D012333:RNA, Messenger; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase