Interaction between Arabidopsis thaliana and Sinorhizobium meliloti for improved plant growth and nitrogen nutrition

KRAISER T; GRAS DE; ZUÑIGA A; O ́BRIEN J; MEDINA M; GONZÁLEZ B; GUTIÉRREZ RA

Congreso; XI Reunion biologia Vegetal Chile; 2016

Nitrogen (N) is an essentialmacronutrient and a major factor limiting plant growth in natural as well as inagricultural environments.  Plants  acquire N  directly  from the  soiland  in a  few  cases N  can  be provided by  N-fixing  bacteria. Plant:bacteria interactions associatedwith N-nutrition are well described in legumes, but are also observed in somenon-legume plant species. We found Arabidopsis thaliana growth under N-limitingconditions is enhanced by Sinorhizobium meliloti RMP110. This  growth enhancement  is in  part  mediated by  bacterial  N-fixation. Dilution  of 15N  labeling when Arabidopsis plants were grownwith S.  meliloti indicated Arabidopsisplants indirectly acquired atmospheric N,  where 14 N isotope predominates. Arabidopsishomologs of key regulatory genes involved in legume:rhizobium interactions are  required for Arabidopsis  growth  promotion mediated  by  S. meliloti.  Our  results suggest  conserved molecular mechanismsexist in plants to interact with N-fixing bacteria for improved growth under N-limitingconditions.