The Casuarina NIN gene is transcriptionally activated throughout Frankia root infection as well as in response to bacterial diffusible signals Clavijo F. auteur aut IRD Diedhiou I. auteur aut IRD Vaissayre Virginie auteur aut IRD Brottier L. auteur aut IRD Acolatse J. auteur aut IRD Moukouanga Daniel auteur aut IRD Crabos Amandine auteur aut IRD Auguy Florence auteur aut IRD Franche Claudine auteur aut IRD Gherbi Hassen auteur aut IRD Champion Antony auteur aut IRD Hocher Valérie auteur aut IRD Barker D. auteur aut IRD Bogusz Didier auteur aut IRD Tisa L. S. auteur aut IRD Svistoonoff Sergio auteur aut IRD text journalArticle eng text/pdf born digital access Root nodule symbioses (RNS) allow plants to acquire atmospheric nitrogen by establishing an intimate relationship with either rhizobia, the symbionts of legumes or Frankia in the case of actinorhizal plants. In legumes, NIN (Nodule INception) genes encode key transcription factors involved in nodulation. Here we report the characterization of CgNIN, a NIN gene from the actinorhizal tree Casuarina glauca using both phylogenetic analysis and transgenic plants expressing either ProCgNIN::reporter gene fusions or CgNIN RNAi constructs. We have found that CgNIN belongs to the same phylogenetic group as other symbiotic NIN genes and CgNIN is able to complement a legume nin mutant for the early steps of nodule development. CgNIN expression is correlated with infection by Frankia, including preinfection stages in developing root hairs, and is induced by culture supernatants. Knockdown mutants were impaired for nodulation and early root hair deformation responses were severely affected. However, no mycorrhizal phenotype was observed and no induction of CgNIN expression was detected in mycorrhizas. Our results indicate that elements specifically required for nodulation include NIN and possibly related gene networks derived from the nitrate signalling pathways. specialized actinorhiza biological nitrogen fixation mycorrhiza nodule inception plant-microbe signalling root hair deformation root nodule symbioses 076 084 New Phytologist 208 3 887-903 2015 0028-646X https://www.documentation.ird.fr/hor/fdi:010065498 10.1111/nph.13506 0028-646X [F B010065498] https://www.documentation.ird.fr/hor/fdi:010065498 https://www.documentation.ird.fr/intranet/publi/2015/12/010065498.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2016-01-14 2017-08-23 fdi:010065498 fre