Burkholderia phytofirmans PsJN regulates Arabidopsis growth through a signaling mechanism dependent of auxin and ethylene
M. POUPIN (1), M. Greve (1), V. Carmona (2), I. Pinedo (2), T. Ledger (2) (1) Facultad de Ingenieria y Ciencias, Universidad Adolfo Ibanez, Chile; CAPES, Chile., Chile; (2) Facultad de Ingenieria y Ciencias, Universidad Adolfo Ibanez, Chile; CAPES, Chile., Chile

Regulation of phytohormones homeostasis is one of the proposed mechanisms to explain plant growth promotion induced by beneficial rhizobacteria (PGPR). Nevertheless, little is known concerning the interplay between phytohormones in plants interacting with PGPR. Recent studies report a complex interplay between auxin and ethylene in the regulation of plant development. Here we studied the role of both hormones in the growth promotion induced by the PGPR Burkholderia phytofirmans PsJN in Arabidopsis thaliana plants. Thus, the spatiotemporal transcriptional patterns of several genes related to auxin biosynthesis, perception and response and ethylene biosynthesis were studied, finding that most of these genes were regulated under PsJN. PsJN-growth promotion was not observed in Arabidopsis mutants with an impaired ethylene or auxin signaling. Even, PsJN did not promote growth in an ethylene overproducer, indicating that a fine regulation of both hormones signaling and homeostasis is necessary to induce growth of the aerial and root tissues. Auxin polar transport is also involved in growth promotion, since PsJN did not promote primary root growth under transport disruption of this hormone. Finally, both hormones act in the PsJN-mediated increase in root hair number and length, where ethylene biosynthesis plays a critical role. Acknowledgements: FONDECYT 11121306; CAPES FB-0002-2014; Millennium Nucleus NC130030.

Abstract Number: P9-295
Session Type: Poster