title: Carotenoid cleavage dioxygenase 7 modulates plant growth, reproduction, senescence, and determinate nodulation in the model legume Lotus japonicus.
abstract: Strigolactones (SLs) are newly identified hormones that regulate multiple aspects of plant development, infection by parasitic weeds, and mutualistic symbiosis in the roots. In this study, the role of SLs was studied for the first time in the model plant Lotus japonicus using transgenic lines silenced for carotenoid cleavage dioxygenase 7 (LjCCD7), the orthologue of Arabidopsis More Axillary Growth 3. Transgenic LjCCD7-silenced plants displayed reduced height due to shorter internodes, and more branched shoots and roots than the controls, and an increase in total plant biomass, while their root:shoot ratio remained unchanged. Moreover, these lines had longer primary roots, delayed senescence, and reduced flower/pod numbers from the third round of flower and pod setting onwards. Only a mild reduction in determinate nodule numbers and hardly any impact on the colonization by arbuscular mycorrhizal fungi were observed. The results show that the impairment of CCD7 activity in L. japonicus leads to a phenotype linked to SL functions, but with specific features possibly due to the peculiar developmental pattern of this plant species. It is believed that the data also link determinate nodulation, plant reproduction, and senescence to CCD7 function for the first time.
authors.affiliation: Department of Agriculture, Forestry and Food Sciences, University of Turin, via Leonardo da Vinci 44, 10095 Grugliasco, TO, Italy.
authors.forename: Junwei
authors.initials: J
authors.lastname: Liu
authors.forename: Mara
authors.initials: M
authors.lastname: Novero
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Charnikhova
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ferrandino
authors.forename: Andrea
authors.initials: A
authors.lastname: Schubert
authors.forename: Carolien
authors.initials: C
authors.lastname: Ruyter-Spira
authors.forename: Paola
authors.initials: P
authors.lastname: Bonfante
authors.forename: Claudio
authors.initials: C
authors.lastname: Lovisolo
authors.forename: Harro J
authors.initials: HJ
authors.lastname: Bouwmeester
authors.forename: Francesca
authors.initials: F
authors.lastname: Cardinale
mesh_terms: D002338:Carotenoids / Q000378:metabolism*; D000070116:Lotus / Q000201:enzymology* / Q000378:metabolism* / Q000382:microbiology; D038821:Mycorrhizae / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000378:metabolism / Q000382:microbiology; D013559:Symbiosis / Q000502:physiology
chemical_list: D010940:Plant Proteins; D002338:Carotenoids