title: Nitrogen fixation persists under conditions of salt stress in transgenic Medicago truncatula plants expressing a cyanobacterial flavodoxin.
abstract: Several recent studies have demonstrated that the expression of a cyanobacterial flavodoxin in plants can provide tolerance to a wide range of environmental stresses. Indeed, this strategy has been proposed as a potentially powerful biotechnological tool to generate multiple-tolerant crops. To determine whether flavodoxin expression specifically increased tolerance to salt stress and whether it might also preserve legume nitrogen fixation under saline conditions, the flavodoxin gene was introduced into the model legume Medicago truncatula. Expression of flavodoxin did not confer saline tolerance to the whole plant, although the sensitive nitrogen-fixing activity was maintained under salt stress in flavodoxin-expressing plants. Our results indicate that flavodoxin induced small but significant changes in the enzymatic activities involved in the nodule redox balance that might be responsible for the positive effect on nitrogen fixation. Expression of flavodoxin can be regarded as a potential tool to improve legume symbiotic performance under salt stress, and possibly other environmental stresses.
authors.affiliation: Department of Plant Physiology and Ecology, Instituto de Recursos Naturales, Centro de Ciencias Medioambientales, CSIC, Serrano, Madrid, Spain.
authors.forename: Teodoro
authors.initials: T
authors.lastname: Coba de la Peña
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Redondo
authors.forename: Esteban
authors.initials: E
authors.lastname: Manrique
authors.forename: M M
authors.initials: MM
authors.lastname: Lucas
authors.forename: José J
authors.initials: JJ
authors.lastname: Pueyo
mesh_terms: D000458:Cyanobacteria / Q000235:genetics*; D005418:Flavodoxin / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D046913:Medicago truncatula / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D009586:Nitrogen Fixation / Q000187:drug effects*; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012492:Salts / Q000494:pharmacology*
chemical_list: D005418:Flavodoxin; D012492:Salts