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.
Kim
Y S
YS
Department of Biology, College of Science, Yonsei University, Seoul, Korea.
Choi
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Lee
M M
MM
Lee
S H
SH
Kim
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WT
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