title: Knock-down of a member of the isoflavone reductase gene family impairs plant growth and nodulation in Phaseolus vulgaris.
abstract: Flavonoids and isoflavonoids participate in the signaling exchange between roots of legumes and nitrogen-fixing rhizobia and can promote division of cortical cells during nodule formation by inhibiting auxin transport. Here, we report the characterization of a member of the common bean isoflavone reductase (EC 1.3.1.45, PvIFR1) gene family, an enzyme that participates in the last steps of the biosynthetic pathway of isoflavonoids. Transcript levels of PvIFR1 were detected preferentially in the susceptible zone of roots, augmented upon nitrogen starvation and in response to Rhizobium etli inoculation at very early stages of the interaction. Knockdown of PvIFR1 mediated by RNA interference (RNAi) in common bean composite plants resulted in a reduction of shoot and root length. Furthermore, reduction of PvIFR1 mRNAs also affected growth of lateral roots after emergence, a stage in which auxins are required to establish a persistent meristem. Upon inoculation, the number of nodules formed by different strains of R. etli was significantly lower in IFR RNAi than in control roots. Transcript levels of two auxin-regulated genes are consistent with lower levels of auxin in PvIFR1 silenced roots. These results suggest a complex role of PvIFR1 during plant growth, root development and symbiosis, all processes in which auxin transport is involved.
authors: Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CCT-La Plata, CONICET, Calle 115 y 49 s/n, CP 1900, La Plata, Buenos Aires, Argentina.
authors: Carolina
authors: C
authors: Rípodas
authors: Virginia Dalla
authors: VD
authors: Via
authors: O Mario
authors: OM
authors: Aguilar
authors: María Eugenia
authors: ME
authors: Zanetti
authors: Flavio Antonio
authors: FA
authors: Blanco
mesh_terms: D000595:Amino Acid Sequence; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics* / Q000378:metabolism; D027805:Phaseolus / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D034622:RNA Interference; D042163:Rhizobium etli / Q000502:physiology; D053204:Root Nodules, Plant / Q000235:genetics* / Q000254:growth & development* / Q000382:microbiology*; D013559:Symbiosis / Q000502:physiology
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; C071072:vestitone reductase; D044925:Oxidoreductases Acting on CH-CH Group Donors