Biological activity of the rolB-like 5' end of the A4-orf8 gene from the Agrobacterium rhizogenes TL-DNA.
The iaaM gene from different plant-associated bacteria encodes a tryptophan monooxygenase (IaaM) that catalyzes the synthesis of indole-3-acetamide (IAM), a precursor of indole-3-acetic acid (IAA). Unlike the IaaM proteins from other bacteria, Agrobacterium spp. T-DNA-encoded IaaM proteins carry a 200 amino acid N-terminal extension with low homology to various members of the RolB protein family. This family is composed of 18 highly divergent T-DNA-encoded proteins, the basic functions of which are still largely undetermined. Deletion of the 5' rolB-like extension of the iaaM gene from Agrobacterium tumefaciens strain Ach5 did not lead to a reduction in IAM synthesis in plants. When expressed in tobacco, the rolB-like fragment did not affect growth or morphology. An iaaM homolog (A4-orf8) from the TL-DNA of Agrobacterium rhizogenes strain A4 also was investigated. Neither the full-size A4-orf8 gene nor the 5'-truncated form induced detectable IAM synthesis. Plants expressing the rolB-like part of the A4-orf8 gene, however, were dwarfed and mottled to various extents and synthesized abnormally high amounts of glucose, fructose, sucrose, and starch.
Department of Cell Biology, Plant Molecular Biology Institute of the CNRS, Strasbourg, France. leon.otten@ibmp-ulp.u-strasbg.fr
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D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D050260:Carbohydrate Metabolism; D004269:DNA, Bacterial / Q000032:analysis; D005798:Genes, Bacterial; D007210:Indoleacetic Acids / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D015513:Oncogene Proteins / Q000235:genetics*; D016366:Open Reading Frames; D018517:Plant Roots / Q000378:metabolism; D010947:Plants, Toxic; D012231:Rhizobium / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D014026:Nicotiana / Q000378:metabolism; D014365:Tryptophan Hydroxylase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001617:beta-Glucosidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D007210:Indoleacetic Acids; D015513:Oncogene Proteins; C036483:T-DNA; C081170:iaaM protein, Agrobacterium; C015950:indoleacetamide; D014365:Tryptophan Hydroxylase; C092241:RolB protein, Agrobacterium rhizogenes; D001617:beta-Glucosidase