title: The aux1 gene of the Ri plasmid is sufficient to confer auxin autotrophy in tobacco BY-2 cells.
abstract: Tobacco (Nicotiana tabacum) Bright Yellow-2 (BY-2) cells are rapidly proliferating meristematic cells that require auxin for culture in vitro. We have established several transgenic BY-2 cell lines that carry the T-DNA of Agrobacterium rhizogenes 15834, which harbors an agropine-type root-inducing (Ri) plasmid. Two of these lines, BYHR-3 and BYHR-7, were used to test the role of auxin in the proliferation of plant cells. The lines grew rapidly in Linsmaier-Skoog (LS) medium lacking auxin and other phytohormones. The TR-DNA, containing the aux1 (tryptophan monooxygenase) and aux2 (indoleacetamide hydrolase) genes, was present in the genomes of both transgenic lines, whereas the TL-DNA, containing the rolA, B, C and D genes, was present in the genome of BYHR-7 but not BYHR-3. Since the introduction of the rolABCD genes alone did not affect the auxin requirement of BY-2 cells, the aux1 and aux2 genes, but not the rolABCD genes, appear to be relevant to the auxin autotrophy of these transgenic lines. Furthermore, the overexpression of aux1 allowed BY-2 cells to grow rapidly in the absence of auxin, suggesting the existence in plant cells of an unidentified gene whose product is functionally equivalent or similar to that of aux2 of the Ri plasmid.
authors.affiliation: Graduate School of Bioscience, Tokai University, 317 Nishino, Numazu, Shizuoka 410-0321, Japan.
authors.forename: Keiichirou
authors.initials: K
authors.lastname: Nemoto
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Hara
authors.forename: Shingo
authors.initials: S
authors.lastname: Goto
authors.forename: Kouji
authors.initials: K
authors.lastname: Kasai
authors.forename: Hikaru
authors.initials: H
authors.lastname: Seki
authors.forename: Masashi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Atsuhiro
authors.initials: A
authors.lastname: Oka
authors.forename: Toshiya
authors.initials: T
authors.lastname: Muranaka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Mano
mesh_terms: D052818:Autotrophic Processes / Q000502:physiology*; D002460:Cell Line; D048430:Cell Shape; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018745:Genome, Plant / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D010957:Plasmids / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014026:Nicotiana / Q000166:cytology* / Q000235:genetics* / Q000254:growth & development
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D018744:DNA, Plant; D007210:Indoleacetic Acids; D010940:Plant Proteins; D012333:RNA, Messenger; C036483:T-DNA