Demonstration of the indolepyruvate decarboxylase gene homologue in different auxin-producing species of the Enterobacteriaceae.
Different Enterobacteriaceae were assayed for their ability to produce the plant hormone indole-3-acetate with the aim to study the distribution of the indole-3-pyruvate pathway, which is known to be involved in the production of indole-3-acetate in a root-associated Enterobacter cloacae strain. Other E. cloacae strains, and also Enterobacter agglomerans strains, Pantoea agglomerans, Klebsiella aerogenes, and Klebsiella oxytoca were found to convert tryptophan into indole-3-acetate. As it was also intended to identify the conserved regions of the indole-3-pyruvate decarboxylase, which is involved in producing indole-3-acetate in the E. cloacae strain, oligonucleotide primers were synthesized for different regions of the corresponding gene. One pair of these primers allowed us to amplify a segment of the predicted size by the polymerase chain reaction with DNA of the seven different Enterobacteriaceae that produce indole-3-acetate. Segments of five strains were cloned and sequenced. All sequences showed significant homology to the indole-3-pyruvate decarboxylase gene. As in addition a positive DNA-DNA hybridization signal was detected in the seven strains using the E. cloacae or E. agglomerans segments as a probe, indole-3-acetate biosynthesis is suggested to be catalyzed via the indole-3-pyruvate pathway not only in E. cloacae but also in the other soil-living Enterobacteriaceae. Conserved regions were detected in the indole-3-decarboxylase by alignment of the now-available five different partial sequences. These regions should enable identification of the gene in other bacterial families or even in plants.
Zimmer
W
W
Botanisches Institut, Universität Köln, Germany.
Hundeshagen
B
B
Niederau
E
E
D000595:Amino Acid Sequence; D001483:Base Sequence; D002262:Carboxy-Lyases / Q000235:genetics*; D017931:DNA Primers; D004755:Enterobacteriaceae / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D007210:Indoleacetic Acids / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D017931:DNA Primers; D007210:Indoleacetic Acids; C068832:indolepyruvate decarboxylase; D002262:Carboxy-Lyases